Correct Answer: (3) Annelida

Explanation: Sponges have a cellular level of organization and lack a nervous system. Coelenterates and Ctenophores have a diffuse nerve net, which is a primitive form of nervous system. Annelids, however, possess a more developed nervous system consisting of paired ganglia and a double ventral nerve cord.

Correct Answer: (3) Hydra, Jelly fish, Starfish

Explanation: Hydra and Jellyfish (Coelenterates) exhibit radial symmetry. Starfish (Echinoderms) also exhibit radial symmetry in their adult stage. Tapeworm, Earthworm, and Cockroach exhibit bilateral symmetry. Sponges are mostly asymmetrical.

Correct Answer: (2) one

Explanation: (a) In an open circulatory system, blood is pumped out of the heart and the cells and tissues are directly bathed in it, not circulated through a series of vessels of varying diameter. This statement is incorrect. (b) Sponges are generally asymmetrical, not bilaterally symmetrical. This statement is incorrect. (c) The description given is for radial symmetry, not bilateral symmetry. Bilateral symmetry means the body can be divided into two identical left and right halves by only one plane. This statement is incorrect. (d) In Platyhelminthes (flatworms), the digestive system is incomplete, meaning they have a single opening that serves as both mouth and anus. This statement is correct. Therefore, only one statement (d) is correct.

Correct Answer: (1) Coelenterates and ctenophores

Explanation: This question refers to a figure that is not provided. However, based on the answer key, the figure likely depicts organisms with radial symmetry or diploblastic organization, which are characteristic of Coelenterates (Cnidaria) and Ctenophores. Without the figure, a precise explanation is difficult, but these two phyla share several common features like radial symmetry and diploblastic nature.

Correct Answer: (3) A – ii, B – iv & i, C – iii

Explanation: A. Triploblastic: Organisms with three germ layers (ectoderm, mesoderm, endoderm). So, A – ii. B. Notochord: A mesodermally derived rod-like structure found in chordates. So, B – iv & i. C. Metamerism: True segmentation, where the body is divided into segments. So, C – iii.

Correct Answer: (2) Mesoderm

Explanation: A true coelom (eucoelom) is a body cavity that is lined by mesoderm on all sides. Pseudocoelomates have a body cavity not fully lined by mesoderm, and acoelomates lack a body cavity.

Correct Answer: (2) Platyhelminthes

Explanation: Cnidaria (Coelenterates) have tissue level of organization. Platyhelminthes (flatworms) are the first group to exhibit organ level of organization. Aschelminthes and Annelida show organ-system level of organization.

Correct Answer: (2) Metamerism

Explanation: Metamerism is the phenomenon of having a linear series of body segments, each fundamentally similar in structure, but not all structures are necessarily repeated in every segment. This is characteristic of annelids, arthropods, and chordates.

Correct Answer: (2) Echinoderms, Arthropoda, Aschelminthes, Annelids are eucoelomates.

Explanation: The incorrect statement is (2). Aschelminthes (roundworms) are pseudocoelomates, meaning their body cavity is not lined by mesoderm. Echinoderms, Arthropoda, and Annelids are eucoelomates (true coelomates).

Correct Answer: (4) Cockroach

Explanation: Tapeworm (Platyhelminthes) is triploblastic but acoelomate and has an incomplete digestive tract. Octopus (Mollusca) is triploblastic, eucoelomate, and has a complete digestive tract, but lacks metameric segmentation. Starfish (Echinodermata) is triploblastic, eucoelomate, and has a complete digestive tract, but lacks metameric segmentation. Cockroach (Arthropoda) is triploblastic, has a complete digestive tract, is eucoelomate, and exhibits metameric segmentation.

Correct Answer: (2) Blind sac body plan

Explanation: A blind sac body plan is characterized by a single opening that functions as both mouth and anus. This is seen in Cnidarians and Platyhelminthes. A tube-within-a-tube plan has two openings, a mouth and an anus.

Correct Answer: (1) Notochord is mesodermally derived structure formed on the dorsal side during development of all invertebrates

Explanation: The incorrect statement is (1). Notochord is a characteristic feature of Chordates, which are vertebrates and some invertebrates (like Urochordates and Cephalochordates), but it is not found in *all* invertebrates. It is a mesodermally derived structure formed on the dorsal side during embryonic development of chordates.

Correct Answer: (1) Arthropoda, mollusca, echinodermata

Explanation: Open circulatory system is found in Arthropoda, most Mollusca (except cephalopods), and Echinodermata. Annelids have a closed circulatory system. Cephalopod molluscs (like Octopus, Squid) have a closed circulatory system.

Correct Answer: (3) A = Cellular level, B = Bilateral, C = Acoelomate, D = Aschelminthes

Explanation: A: The chart shows “Tissue/Organ/Organ system” as a level of organization. The other primary level of organization is “Cellular level,” which is characteristic of Porifera. So, A = Cellular level. B: The chart shows “Radial” symmetry for Coelenterata and Ctenophora. The other main type of symmetry is “Bilateral.” So, B = Bilateral. C: The chart lists “Platyhelminthes” under “Without body cavity.” This means Platyhelminthes are “Acoelomate.” So, C = Acoelomate. D: The chart lists “Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata” under “With true coelom (coelomates).” The group “With false coelom (pseudocoelomates)” is missing, and Aschelminthes are pseudocoelomates. So, D = Aschelminthes.

Correct Answer: (1) Radial

Explanation: While most sponges are asymmetrical, Sycon and Leucosolenia (both sponges) exhibit radial symmetry.

Correct Answer: (2) They have a water vascular system

Explanation: Porifera (sponges) have a water canal system (or water transport system), not a water vascular system. The water vascular system is a characteristic feature of Echinodermata.

Correct Answer: (3) a, b, c and d

Explanation: (a) Cellular level of organisation: Exclusive to Porifera. (b) Ostia: Pores on the body surface for water entry, exclusive to Porifera. (c) Spongocoel: Central cavity of sponges, exclusive to Porifera. (d) Choanocytes (collar cells): Unique flagellated cells lining the spongocoel and canals, exclusive to Porifera. (e) Hermaphrodite animals: While many sponges are hermaphrodites, this is not exclusive to Porifera (e.g., Earthworm). (f) Internal fertilisation: Occurs in many other phyla as well, not exclusive. Therefore, a, b, c, and d are exclusive features.

Correct Answer: (2) Intracellular Extracellular Intracellular

Explanation: In Porifera, digestion is exclusively intracellular. In Coelenterata, digestion is both extracellular (in the gastrovascular cavity) and intracellular (within nutritive cells).

Correct Answer: (2) Coelenterata

Explanation: The presence of cnidoblasts (stinging cells) on tentacles is a defining characteristic of the phylum Coelenterata (also known as Cnidaria). They also fit the description of being aquatic, mostly marine, sessile or free-swimming, and radially symmetrical.

Correct Answer: (4) a – iv; b – ii,iii; c – i,ii

Explanation: a. Porifera: Characterized by Spongocoel (iv). b. Coelenterate: Diploblastic (ii) and possess Cnidoblasts (iii). c. Ctenophore: Commonly known as Sea walnuts (i) and are Diploblastic (ii).

Correct Answer: (3) Digestion is only intracellular

Explanation: Ctenophores exhibit both extracellular and intracellular digestion. The other options are correct characteristics of Ctenophora.

Correct Answer: (3) Sycon —— Bath sponge

Explanation: Meandrina (Brain coral), Pennatula (Sea pen), and Gorgonia (Sea fan) are all members of Phylum Coelenterata (Cnidaria). Sycon is a member of Phylum Porifera (sponges). Bath sponge is Euspongia, not Sycon.

Correct Answer: (1) a – polyp; b – medusa; c – sessile; d – cylindrical; e – Umbrella shaped; f – Free swimming

Explanation: Cnidarians exhibit two basic body forms: polyp and medusa. The polyp is sessile and cylindrical, while the medusa is umbrella-shaped and free-swimming.

Correct Answer: (3) Coelenterata —– gastrovascular cavity — Cnidoblasts —- direct development — Obelia

Explanation: The incorrect match is (3). Coelenterates (Cnidarians) typically exhibit indirect development, meaning they have a larval stage. Obelia, for example, has a planula larva. Direct development is not a general characteristic of Coelenterata.

Correct Answer: (1) Ctenophora

Explanation: Ctenophores reproduce only by sexual means. Coelenterates and Porifera can reproduce both asexually and sexually. Protozoa reproduce primarily asexually, though some exhibit sexual processes.

Correct Answer: (3) Extracellular and intracellular digestion

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the common character among the depicted animals (likely Coelenterates and Ctenophores) is extracellular and intracellular digestion. Cnidoblasts are exclusive to Cnidaria, ciliary comb plates to Ctenophora, and bioluminescence is prominent in Ctenophora but not universal across all Coelenterates.

Correct Answer: (4) Cellular level of organisation

Explanation: Coelenterates (Cnidaria) exhibit tissue level of organization, not cellular level. Cellular level of organization is characteristic of Porifera.

Correct Answer: (4) Pleurobrachia

Explanation: Sycon, Spongilla, and Euspongia are all examples of sponges (Phylum Porifera). Pleurobrachia is a comb jelly, belonging to Phylum Ctenophora.

Correct Answer: (4) Have highly porous body

Explanation: Sponges have a highly porous body with a water canal system. Water continuously flows through these pores, bringing in oxygen and food, and carrying away waste products. This efficient water flow allows for direct exchange of gases with the environment, eliminating the need for specialized respiratory organs.

Correct Answer: (4) All 1, 2 and 3

Explanation: Cnidoblasts (or nematocysts) in Cnidarians serve multiple functions: anchorage to substratum, defense against predators, and capture of prey by stinging or entangling them.

Correct Answer: (3) Taenia

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the cross-section likely depicts an acoelomate body plan, which is characteristic of Taenia (tapeworm), a Platyhelminth. Cockroach and Earthworm are coelomates, and Roundworm is a pseudocoelomate.

Correct Answer: (2) excretion by Malpighian body

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the diagram likely represents a Platyhelminth (flatworm). Platyhelminthes are dorsoventrally flat, bilaterally symmetrical, and exhibit internal fertilization with indirect development. Excretion in Platyhelminthes occurs through flame cells, not Malpighian bodies. Malpighian tubules are excretory organs found in insects (Arthropods).

Correct Answer: (1) Rounded unsegmented body, muscular pharynx, pseudocoelomate, females are longer than males

Explanation: Aschelminthes (Nematoda or roundworms) are characterized by a rounded, unsegmented body, a muscular pharynx, a pseudocoelom (false body cavity), and typically, females are longer than males.

Correct Answer: (1) two

Explanation: The characters are: (a) Organ system level, (b) Sexes separate (dioecious), (c) Internal fertilization, (d) Bilateral symmetry, (e) Pseudocoelomate. * **Ascaris** (Roundworm): (a) Yes, (b) Yes, (c) Yes, (d) Yes, (e) Yes. (Fits all) * **Ancylostoma** (Hookworm): (a) Yes, (b) Yes, (c) Yes, (d) Yes, (e) Yes. (Fits all) * **Nereis** (Annelid): (e) No (eucoelomate). * **Earthworm** (Annelid): (b) No (hermaphrodite), (e) No (eucoelomate). * **Taenia** (Tapeworm, Platyhelminthes): (a) No (organ level), (b) No (hermaphrodite), (e) No (acoelomate). * **Liver fluke** (Platyhelminthes): (a) No (organ level), (b) No (hermaphrodite), (e) No (acoelomate). Only Ascaris and Ancylostoma fit all the given criteria. So, two animals.

Correct Answer: (3) Flame cells —- help in excretion

Explanation: The incorrect match is (3). Flame cells are specialized excretory structures found in Platyhelminthes (flatworms). In Annelids, excretion and osmoregulation are carried out by nephridia.

Correct Answer: (1) a – correct, b — incorrect, c — incorrect, d — correct

Explanation: (a) Tapeworm (Platyhelminthes) is dorsoventrally flat. (Correct) (b) Planaria (Platyhelminthes) has a very high regeneration capacity. (Incorrect) (c) Ascaris (Aschelminthes) is triploblastic but pseudocoelomate, not acoelomate. (Incorrect) (d) Nereis (Annelida) is an aquatic form and is dioecious (sexes are separate). (Correct) Therefore, options (a) and (d) are correct, while (b) and (c) are incorrect.

Correct Answer: (1) Possess lateral appendages, parapodia which help in reproduction

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the diagram likely represents an Annelid, specifically Nereis. Parapodia in Nereis are primarily involved in locomotion (swimming) and respiration, not reproduction. Reproduction in Nereis is sexual. The other statements are correct for Annelids: segmented body, closed circulatory system, and nephridia for excretion/osmoregulation.

Correct Answer: (4) a – iii,u; b – i,w; c – ii,v

Explanation: a. Platyhelminthes: (iii) tapeworm, (u) Taenia. b. Aschelminthes: (i) roundworm, (w) Ascaris. c. Annelida: (ii) earthworm, (v) Pheretima.

Correct Answer: (2) Aschelminthes

Explanation: The description “circular in cross section,” “bilaterally symmetrical,” and “pseudocoelomate” are key characteristics of animals belonging to the phylum Aschelminthes (Nematoda or roundworms).

Correct Answer: (4) Wuchereria

Explanation: Nereis, Pheretima (Earthworm), and Hirudinaria (Leech) are all members of Phylum Annelida. Wuchereria (Filarial worm) is a member of Phylum Aschelminthes (Nematoda).

Correct Answer: (3) Blood sucking leech, neural system consists of paired ganglia connected by lateral nerves to a double ventral nerve cord

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the diagram likely depicts a leech (Hirudinaria), which is an annelid. Annelids, including leeches, have a nervous system characterized by paired ganglia and a double ventral nerve cord.

Correct Answer: (3) Limulus

Explanation: Limulus (King crab) is an arthropod, and arthropods typically have an open circulatory system. Myxine (Hagfish) is a cyclostome (vertebrate) with a closed circulatory system. Pheretima (Earthworm) and Nereis are annelids, which have a closed circulatory system.

Correct Answer: (4) d

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the diagram likely represents a Platyhelminth (flatworm), such as a tapeworm or liver fluke. (a) Hooks and suckers are present in parasitic flatworms (e.g., Taenia). (Related) (b) Parasitic flatworms absorb nutrients directly through their body surface. (Related) (c) Flame cells are characteristic excretory organs of Platyhelminthes. (Related) (d) Platyhelminthes are typically hermaphrodites (sexes are united), not dioecious (sexes separate). Therefore, “Sexes are separate” is NOT related to Platyhelminthes.

Correct Answer: (2) Pseudocoel

Explanation: Roundworms (Aschelminthes) are pseudocoelomates, possessing a false body cavity. Flatworms (Platyhelminthes) are acoelomates, lacking a body cavity. Neither has a circulatory system or dorsal nerve cord. Flame cells are characteristic of flatworms, not roundworms.

Correct Answer: (4) sanguivorous

Explanation: Hirudinaria (the Indian cattle leech) is sanguivorous, meaning it feeds on blood.

Correct Answer: (1) Hemichordata

Explanation: The proboscis gland (also known as glomerulus) is the excretory organ in Hemichordata.

Correct Answer: (1) a – radially symmetrical, b – bilaterally symmetrical

Explanation: Echinoderms exhibit a unique characteristic where their adult forms are radially symmetrical (typically pentaradial), but their larval stages are bilaterally symmetrical.

Correct Answer: (2) Mollusca

Explanation: The radula, a chitinous ribbon-like structure bearing teeth, is a characteristic feeding organ found in most molluscs (except bivalves).

Correct Answer: (4) Arthropoda

Explanation: All the given characteristics (bilateral symmetry, triploblastic, segmented, coelomate, open circulatory system, excretion by Malpighian tubules, and paired jointed appendages) are defining features of the phylum Arthropoda.

Correct Answer: (3) they are pseudocoelomate

Explanation: Echinoderms are eucoelomates (true coelomates), not pseudocoelomates. The other statements are correct characteristics of Echinodermata: presence of a water vascular system, an internal skeleton (ossicles), and bilateral symmetry in their larval stage.

Correct Answer: (4) b , c

Explanation: (a) Molluscs are bilaterally symmetrical and triploblastic, but they are coelomate (though the coelom is reduced), not acoelomate. So, (a) is incorrect. (b) The body of molluscs is typically covered by a calcareous shell (though some may lack it), is unsegmented, and has a distinct head, visceral hump (or mass), and muscular foot. So, (b) is correct. (c) The mouth of most molluscs contains a radula for feeding. So, (c) is correct. (d) Lithocysts are statocysts (balance organs) found in some invertebrates, but the description “over stalk for testing chemical and physical nature of water” is not a general or exclusive feature of molluscs. Osphradia are chemoreceptors in some molluscs. So, (d) is incorrect. Therefore, only (b) and (c) are correct.

Correct Answer: (1) A – IV; B – III; C – II; D – I

Explanation: A. Apis: Honey bee (IV) B. Bombyx: Silk worm (III) C. Laccifer: Lac insect (II) D. Limulus: King crab (I)

Correct Answer: (1) True notochord is present

Explanation: The incorrect statement is (1). Hemichordates were once considered a subphylum under Chordata due to the presence of a structure in the collar region called stomochord, which was thought to be a notochord. However, it is now considered a separate phylum, and the stomochord is not a true notochord. They do not possess a true notochord. The other statements are generally correct for hemichordates: indirect development, fossorial (burrowing) nature, and absence of a post-anal tail.

Correct Answer: (3) Periplanata Jointed appandages Arthropoda Chitinous exoskeleton

Explanation: (1) Pila (Mollusca) is unsegmented, not segmented. So, incorrect. (2) Asterias (Echinodermata) has spiny skin and a water vascular system (not water canal system, which is for sponges). So, incorrect. (3) Periplanata (Cockroach) belongs to Arthropoda, which are characterized by jointed appendages and a chitinous exoskeleton. So, correct. (4) Saccoglossus (Hemichordata) lacks a post-anal tail. So, incorrect.

Correct Answer: (1) A – Locusta , B – Butterfly , C – scorpion , D – Prawn

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the option (1) correctly identifies the animals typically represented by these figures in biology texts: Locusta (locust), Butterfly, Scorpion, and Prawn, all belonging to Arthropoda.

Correct Answer: (1) Pila Octopus Asterias Ophiura

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the option (1) correctly identifies the animals typically represented by these figures in biology texts: Pila (snail), Octopus, Asterias (starfish), and Ophiura (brittle star).

Correct Answer: (2) Having bilaterally symmetrical body

Explanation: This question refers to a diagram that is not provided. However, based on the answer key, the figure likely represents an animal with bilateral symmetry, such as a flatworm or roundworm. Without the figure, a precise explanation is difficult, but bilateral symmetry is a fundamental characteristic for many invertebrate groups.

Correct Answer: (3) Jointed appandages and chitinous exoskeleton

Explanation: Silverfish (Insecta), Scorpion (Arachnida), Dragonfly (Insecta), and Prawn (Crustacea) all belong to the phylum Arthropoda. The defining characteristics of Arthropoda are the presence of jointed appendages and a chitinous exoskeleton. Other options are specific to certain sub-groups within Arthropoda (e.g., three pairs of legs for insects, antennae for insects/crustaceans, cephalothorax for arachnids/crustaceans, trachea for insects/myriapods).

Correct Answer: (2) Pila , Pinctada , Sepia

Explanation: (1) Pila (Mollusca), Octopus (Mollusca), Balanoglossus (Hemichordata). Not same phylum. (2) Pila (Snail), Pinctada (Pearl oyster), Sepia (Cuttlefish) are all members of Phylum Mollusca. (Same phylum) (3) Pila (Mollusca), Asterias (Echinodermata), Ophiura (Echinodermata). Not same phylum. (4) Saccoglossus (Hemichordata), Loligo (Mollusca), Octopus (Mollusca). Not same phylum.

Correct Answer: (4) Paired appendages

Explanation: Echinoderms do not possess paired appendages. Paired appendages are characteristic of Arthropods and Chordates. Water vascular system, pedicellariae (pincer-like structures), and autotomy (self-amputation of body parts) are all characteristic features of echinoderms.

Correct Answer: (4) All of the above

Explanation: The four fundamental characteristics of Chordates are the presence of a notochord, a dorsal hollow nerve cord, paired pharyngeal gill slits, and a post-anal tail (though the tail may be absent in adults of some species).

Correct Answer: (4) Chordata

Explanation: The presence of a post-anal tail and a closed circulatory system, along with bilateral symmetry, triploblastic nature, coelomate body, and organ system level of organization, are all characteristic features of the phylum Chordata.

Correct Answer: (2) Heart is dorsal Heart is ventral

Explanation: The incorrect difference is (2). In chordates, the heart is typically ventral, while in many non-chordates (like annelids and arthropods), the heart is dorsal. The other statements correctly describe differences between chordates and non-chordates.

Correct Answer: (3) Cyclostomata

Explanation: The phylum Chordata is divided into three subphyla: Urochordata (Tunicata), Cephalochordata, and Vertebrata. Cyclostomata is a class within the subphylum Vertebrata, not a subphylum itself.

Correct Answer: (1) Ascidia

Explanation: Ascidia belongs to Urochordata (Tunicata), where the notochord is present only in the larval tail and disappears in the adult. Lancelets (Cephalochordata) have a notochord extending from head to tail and persisting throughout life. Hagfish and Trygon are vertebrates, where the notochord is replaced by a vertebral column in adults.

Correct Answer: (2) c, d

Explanation: (a) Ventral muscular heart: Correct for vertebrates. (b) Bony/cartilaginous vertebral column: Correct for vertebrates (replaces notochord). (c) Radula for feeding: Incorrect. Radula is found in Mollusca, not a characteristic of vertebrates. (d) Paired jointed appendages: Incorrect. While vertebrates have paired appendages (fins/limbs), they are not necessarily “jointed appendages” in the same sense as arthropods, and this is not a universal defining feature for *all* vertebrates (e.g., snakes lack limbs). The question asks for the *wrong* characteristic. Therefore, (c) and (d) are the incorrect characteristics for vertebrates.

Correct Answer: (2) Cyclostomata

Explanation: All living members of the class Cyclostomata (e.g., Lampreys and Hagfishes) are ectoparasites or scavengers on some fishes.

Correct Answer: (2) i – D; ii – E; iii – B; iv – C; v – A

Explanation: i. Petromyzon: Lamprey (D) ii. Myxine: Hagfish (E) iii. Pristis: Saw fish (B) iv. Carcharodon: White shark (C) v. Trygon: Sting ray (A)

Correct Answer: (2) Body is devoid of scales but paired fins are present

Explanation: The incorrect statement is (2). Cyclostomes are characterized by a body devoid of scales and *paired fins are absent*. They have median fins but lack paired pectoral and pelvic fins. The other statements are correct for Cyclostomata.

Correct Answer: (3) If the assertion is true but the reason is false.

Explanation: Assertion: Cyclostomes (like Lampreys) are marine but migrate to freshwater for spawning. This statement is true. Reason: After spawning in freshwater, their larvae (ammocoetes) metamorphose and then migrate back to the ocean. The metamorphosis occurs in freshwater, not marine water. So, the reason is false.

Correct Answer: (3) five

Explanation: (a) Streamlined body: Correct for Osteichthyes (bony fishes). (b) Four pairs of gills: Correct, covered by an operculum on each side. (c) Air bladder is present: Correct, helps in buoyancy. (d) In males pelvic fins bear claspers: Incorrect. Claspers are found in Chondrichthyes (cartilaginous fishes), not Osteichthyes. (e) Two chambered heart: Correct, one atrium and one ventricle. (f) Fertilization is usually external: Correct for most bony fishes. So, five statements (a, b, c, e, f) are correct.

Correct Answer: (2) two

Explanation: We need to find statements *not* related to Chondrichthyes (cartilaginous fishes). (a) terminal mouth: Incorrect for Chondrichthyes (they have a ventral mouth). So, this statement is NOT related. (b) placoid scales on skin: Correct for Chondrichthyes. (c) presence of air bladder: Incorrect for Chondrichthyes (air bladder is absent). So, this statement is NOT related. (d) poikilothermal: Correct for Chondrichthyes (cold-blooded). (e) internal fertilization: Correct for Chondrichthyes. (f) vivipary: Correct for some Chondrichthyes (some are viviparous). Therefore, statements (a) and (c) are not related to Chondrichthyes. There are two such statements.

Correct Answer: (3) Pristis

Explanation: Pristis (Sawfish) is a cartilaginous fish (Chondrichthyes), and internal fertilization is characteristic of this class. Catla, Pterophyllum (Angel fish), and Exocoetus (Flying fish) are bony fishes (Osteichthyes), which typically exhibit external fertilization.

Correct Answer: (1) Lamprey

Explanation: Lampreys (Petromyzon) are marine but migrate to freshwater for spawning (anadromous migration). Myxine (Hagfish) is marine and does not migrate for spawning in the same way. Torpedo (Electric ray) and Trygon (Stingray) are marine cartilaginous fishes that do not exhibit this migratory pattern for spawning.

Correct Answer: (1) Scoliodon

Explanation: The characteristics listed (placoid scales, ventral mouth, absence of air bladder) are all features of cartilaginous fishes (Chondrichthyes). Scoliodon (Dogfish) is a cartilaginous fish. Catla, Exocoetus (Flying fish), and Labeo (Rohu) are all bony fishes (Osteichthyes), which have cycloid/ctenoid scales, terminal mouth, and an air bladder.

Correct Answer: (2) i – e; ii – d; iii – a; iv – b; v – c

Explanation: i. Bufo: Toad (E) ii. Rana: Common Indian frog (D) iii. Hyla: Tree frog (A) iv. Salamandra: Salamander (B) v. Ichthyophis: Limbless amphibian (C)

Correct Answer: (2) six

Explanation: Reptiles in the list: * Chelone (Turtle) * Calotes (Garden lizard) * Testudo (Tortoise) * Alligator * Chameleon * Bangarus (Krait) Non-reptiles: Columba (Pigeon – Aves), Canis (Dog – Mammalia), Struthio (Ostrich – Aves), Felis (Cat – Mammalia), Corvus (Crow – Aves), Ornithorhynchus (Platypus – Mammalia). There are 6 reptiles.

Correct Answer: (1) 6

Explanation: Vivipary means giving birth to live young. This is characteristic of most mammals. * Pteropus (Flying fox – Mammal): Viviparous * Camelus (Camel – Mammal): Viviparous * Delphinus (Dolphin – Mammal): Viviparous * Macropus (Kangaroo – Mammal): Viviparous * Ornithorhynchus (Platypus – Mammal): Oviparous (egg-laying) * Neophron (Vulture – Aves): Oviparous * Aptenodytes (Penguin – Aves): Oviparous * Rattus (Rat – Mammal): Viviparous * Equus (Horse – Mammal): Viviparous So, 6 animals (Pteropus, Camelus, Delphinus, Macropus, Rattus, Equus) show vivipary.

Correct Answer: (3) 4

Explanation: Pneumatic bones (bones with air cavities) are a characteristic feature of birds (Aves) to reduce body weight for flight. * Naja (Cobra – Reptile): No * Corvus (Crow – Aves): Yes * Psittacula (Parrot – Aves): Yes * Pavo (Peacock – Aves): Yes * Calotes (Garden lizard – Reptile): No * Bufo (Toad – Amphibian): No * Hyla (Tree frog – Amphibian): No * Felis (Cat – Mammal): No * Balaenoptera (Blue whale – Mammal): No * Neophron (Vulture – Aves): Yes So, 4 animals (Corvus, Psittacula, Pavo, Neophron) show pneumatic bones.

Correct Answer: (1) Migration from freshwater to marine water

Explanation: Catadromous migration refers to the migration of fish from freshwater to marine water for spawning. Anadromous migration is the opposite (marine to freshwater for spawning).

Correct Answer: (4) mammary glands

Explanation: The presence of mammary glands for milk production is the most universal and defining characteristic of mammals, without known exceptions. While most mammals have seven cervical vertebrae, there are exceptions (e.g., manatees and sloths). Body hair is also a characteristic, but some aquatic mammals have very reduced hair. Corpus callosum is present in placental mammals but absent in monotremes and marsupials.

Correct Answer: (4) i – d; ii – c; iii – e; iv – a; v – b

Explanation: i. Chelone: Turtle (d) ii. Testudo: Tortoise (c) iii. Chameleon: Tree lizard (e) iv. Calotes: Garden lizard (a) v. Crocodilus: Crocodile (b)

Correct Answer: (2) i/b/k; ii/c/k; iii/d/k; iv/a/l

Explanation: i. Naja: Cobra (b), Poisonous (k) ii. Bangarus: Krait (c), Poisonous (k) iii. Vipera: Viper (d), Poisonous (k) iv. Python: Ajgar (a), Non-poisonous (l)

Correct Answer: (3) oviparity and direct development

Explanation: The incorrect characteristic is (3). While amphibians are oviparous (egg-laying), their development is typically indirect, involving a larval stage (e.g., tadpole) that undergoes metamorphosis. Direct development is not a general feature. The other statements are correct characteristics of amphibians.

Correct Answer: (3) oviparity / indirect development

Explanation: The incorrect feature is (3). While reptiles are primarily oviparous (egg-laying), their development is typically direct, meaning there is no larval stage. Indirect development is not a feature of reptiles. The other statements are correct for reptiles.

Correct Answer: (3) 7

Explanation: * Presence of feathers: Yes (Aves) * Beak: Yes (Aves) * Pneumatic bones: Yes (Aves) * Crop: Yes (Aves, for food storage) * Gizzard: Yes (Aves, for grinding food) * Homeothermal (warm-blooded): Yes (Aves) * Oviparity (egg-laying): Yes (Aves) * External fertilization: No (Aves have internal fertilization) So, 7 characters are related to Aves.

Correct Answer: (3) Nine

Explanation: * Muscular diaphragm: Yes * Seven cervical vertebrae: Yes * Mammary glands: Yes * Body hair: Yes * Oviparity: No (Humans are viviparous) * Corpus callosum: Yes * Four chambered heart: Yes * Direct development: Yes * Thecodont dentition: Yes * One pair of forelimbs and one pair of hindlimbs: Yes Total correct characteristics: 9.

Correct Answer: (3) corpus callosum

Explanation: * Four chambered heart: Both crocodiles and humans have a four-chambered heart. (Similarity) * Thecodont dentition (teeth set in sockets): Both crocodiles and humans have thecodont dentition. (Similarity) * Corpus callosum: This is a band of nerve fibers connecting the two cerebral hemispheres, found only in placental mammals (like humans). It is absent in reptiles like crocodiles. (Not a similarity) * 2 pairs of limbs: Both crocodiles and humans have two pairs of limbs (forelimbs and hindlimbs). (Similarity) Therefore, the corpus callosum is not a similarity.

Correct Answer: (2) i – e; ii – d; iii – c; iv – b; v – a

Explanation: There seems to be a typo in the question with “Struthio” listed twice. Assuming the second “Struthio” should be “Psittacula” (Parrot) based on the options and common examples: i. Corvus: Crow (e) ii. Columba: Pigeon (d) iii. Struthio: Ostrich (b) iv. Psittacula (assuming this is the intended animal for ‘c’): Parrot (c) v. Neophron: Vulture (a) If we strictly follow the given options, and assume the second Struthio is a typo and should be Psittacula, then option (2) is the closest match. If the second Struthio is indeed Struthio, then the question is flawed as Struthio is Ostrich (b), and ‘c’ (Parrot) would be unmatched. Given the answer key, the interpretation that the second ‘Struthio’ maps to ‘c’ (Parrot) is incorrect, and the correct mapping for ‘Struthio’ is ‘b’ (Ostrich). Let’s re-evaluate based on the provided answer key and the most logical mapping. Correct mapping based on common knowledge: i. Corvus – e (Crow) ii. Columba – d (Pigeon) iii. Struthio – b (Ostrich) v. Neophron – a (Vulture) This leaves ‘c’ (Parrot) and ‘iv’ (Struthio) as problematic. However, if we assume the question intends to match ‘iii’ to ‘b’ and ‘iv’ to ‘c’ (Parrot), then the option (2) is the only one that aligns with the first two and last one correctly. Let’s re-check the answer key. The answer key says (2). (2) i – e; ii – d; iii – c; iv – b; v – a This means: Corvus -> Crow (e) – Correct Columba -> Pigeon (d) – Correct Struthio (iii) -> Parrot (c) – INCORRECT (Struthio is Ostrich) Struthio (iv) -> Ostrich (b) – Correct Neophron -> Vulture (a) – Correct The question has a definite error with ‘Struthio’ appearing twice and the mapping in option (2) for ‘iii’ being incorrect. However, if we are forced to choose the “most correct” option given the answer key, and assuming a typo in the question where ‘iii’ should be Psittacula (Parrot), then (2) would be correct. But as written, ‘iii’ is Struthio, which is Ostrich. Let’s assume the question meant: i Corvus -> e Crow ii Columba -> d Pigeon iii Psittacula -> c Parrot iv Struthio -> b Ostrich v Neophron -> a Vulture If this is the case, then option (2) would be correct. Given the provided answer key, we must assume there’s an implicit correction or a specific interpretation intended by the question setter. The most common interpretation of such a question with a repeated entry is that one of them is a typo and should be another animal. If we assume ‘iii’ is a typo for Psittacula, then (2) works.

Correct Answer: (2) Canis —— Tiger

Explanation: (1) Felis is the genus for domestic cats. (Correct) (2) Canis is the genus for dogs, wolves, and jackals. Tiger belongs to the genus Panthera (Panthera tigris). (Incorrect) (3) Rattus is the genus for rats. (Correct) (4) Pteropus is the genus for flying foxes (fruit bats). (Correct)

Correct Answer: (2) If both the assertion and reason are true but the reason is not a correct explanation of the assertion.

Explanation: Assertion: Acraniata (Protochordata) is a group of organisms that lack a distinct cranium (brain box). This is true. Reason: Acraniata includes Urochordata and Cephalochordata, which are small, marine, and lack a well-defined head. This is also true. However, the reason (lack of head) does not directly explain *why* they lack a cranium. The lack of a cranium is a defining feature of the group, and the lack of a distinct head is another characteristic, but not a direct explanation for the absence of a cranium.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: The digestive system of Platyhelminthes is incomplete. This is true. Reason: An incomplete digestive system means there is only a single opening that functions as both mouth and anus. This is the definition of an incomplete digestive system and directly explains why it’s called incomplete. So, the reason is a correct explanation of the assertion.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: Coelenterates, Ctenophores, and adult Echinoderms exhibit radial symmetry. This is true. Reason: The definition of radial symmetry is that any plane passing through the central axis of the body divides the animal into two identical halves. This directly explains the assertion. So, the reason is a correct explanation of the assertion.

Correct Answer: (3) If the assertion is true but the reason is false.

Explanation: Assertion: Fertilization in bony fishes (Osteichthyes) is usually external. This is true. Reason: Claspers are present in males of cartilaginous fishes (Chondrichthyes) for internal fertilization, not in bony fishes. So, the reason is false.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: Ascidia belongs to the subphylum Urochordata. This is true. Reason: A defining characteristic of Urochordata is that the notochord is present only in the larval tail. This directly explains why Ascidia (a Urochordate) is classified as such. So, the reason is a correct explanation of the assertion.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: Aschelminthes are pseudocoelomate. This is true. Reason: A pseudocoelom is a body cavity that is not fully lined by mesoderm; instead, the mesoderm is present as scattered pouches between the ectoderm and endoderm. This directly explains the term “pseudocoelomate.” So, the reason is a correct explanation of the assertion.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: Phyla from Porifera to Echinodermata are collectively grouped as non-chordates. This is true. Reason: The defining characteristic of non-chordates is the absence of a notochord (and other chordate features) at any stage of their life cycle. This directly explains why they are classified as non-chordates. So, the reason is a correct explanation of the assertion.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: Most sponges are asymmetrical. This is true. Reason: Asymmetry means that the body cannot be divided into two equal halves by any plane passing through the center. This is the definition of asymmetry and directly explains the assertion. So, the reason is a correct explanation of the assertion.

Correct Answer: (3) If the assertion is true but the reason is false.

Explanation: Assertion: Platyhelminthes are known as flatworms. This is true. Reason: Flatworms have a dorsoventrally flattened body, not laterally compressed. Laterally compressed means flattened from side to side (like a fish). So, the reason is false.

Correct Answer: (1) If both the assertion and the reason are true and the reason is a correct explanation of the assertion.

Explanation: Assertion: Amphibian skin is generally moist. This is true. Reason: Moist skin is essential for cutaneous respiration (gas exchange through the skin), which is a significant mode of respiration in amphibians. This directly explains why their skin is moist. So, the reason is a correct explanation of the assertion.