31 Years NEET Previous Year Questions: Animal Kingdom - 1 - NEET MCQ

To solve this matching question, we must evaluate each term in List I and determine its corresponding class or phylum in List II. Let's analyze each match:

Pleurobrachia: Pleurobrachia is a genus that belongs to the phylum Ctenophora, which is commonly known as comb jellies. Thus, A should be matched with II (Ctenophora).
Radula: A radula is a toothed, chitinous organ found within mollusks that is used for scraping or cutting food before the food enters the esophagus. Hence, B should be matched with I (Mollusca).
Stomochord: The stomochord is a small, tubular structure found in the collar of hemichordates, a fundamental character previously thought to link hemichordates and chordates. Therefore, C should be matched with IV (Hemichordata).
Air bladder: The air bladder, or swim bladder, is a gas-filled sac present in many bony fish that helps to maintain buoyancy. Hence, D should be matched with III (Osteichthyes, a class of bony fish).

Now, let's review the options given:

• Option A: A-IV, B-II, C-III, D-I
• Option B: A-II, B-I, C-IV, D-III
• Option C: A-II, B-IV, C-I, D-III
• Option D: A-IV, B-III, C-II, D-I

The correct matches, based on the classification should be: A-II, B-I, C-IV, D-III. Therefore, the correct answer is: Option B

Let's evaluate each statement with regard to the type of body cavity they describe:

A. Annelids are true coelomates: This statement is correct. Annelids (segmented worms, including earthworms) possess a true coelom, which is a body cavity fully lined with a mesodermal layer more specifically called peritoneum. This allows for the distinction of the internal organs from the body wall, and it facilitates greater complexity and organization of the internal structures.

B. Poriferans are pseudocoelomates: This statement is incorrect. Poriferans (sponges) do not have any type of body cavity. Sponges are at a basic level of complexity and lack true tissues and organs, including a coelom or a pseudocoelom. They are considered to have no body cavity and are thus neither coelomates nor pseudocoelomates.

C. Aschelminthes are acoelomates: This statement is incorrect. Aschelminthes, more commonly referred to as Nematoda or roundworms, are actually pseudocoelomates. They possess a pseudocoelom, which is a body cavity that is not entirely lined by mesodermal tissue, unlike a true coelom. The pseudocoel serves as a rudimentary circulatory system and provides a space for internal organs.

D. Platyhelminthes are pseudocoelomates: This statement is incorrect. Platyhelminthes (flatworms) are acoelomates, meaning they lack any body cavity. Their bodies are solid between the digestive tract and the body wall, lacking a filled cavity that would separate these structures.

From the analysis above, only statement A is accurate:

• A. Annelids are true coelomates - Correct
• B. Poriferans are pseudocoelomates - Incorrect
• C. Aschelminthes are acoelomates - Incorrect
• D. Platyhelminthes are pseudocoelomates - Incorrect

Thus, the correct answer to the question is: Option B

The correct answer is Option C: B, D & E only. Here's why:

B. Notochord is absent: This is the defining characteristic of non-chordates. Chordates possess a notochord at some stage of their development, while non-chordates do not.
D. Heart is dorsal if present: In non-chordates with a circulatory system, the heart is located on the dorsal (back) side of the body, unlike chordates where it's ventral (front).
E. Post anal tail is absent: Non-chordates lack a post-anal tail, a feature present in chordates.

Why the other options are incorrect:

A. Pharynx is perforated by gill slits: This is a characteristic of chordates, particularly in aquatic forms for respiration.
C. Central nervous system is dorsal: While this is true for chordates, non-chordates have a ventral nerve cord.

Let's analyze the match between the items in List I and those in List II. We will specifically address the scientific names provided in List I and match them with their common names given in List II:

List I (Scientific Names) with List II (Common Names):

• Pterophyllum (A) - Angel fish (III): Pterophyllum is the scientific name for a type of cichlid commonly called angel fish. Therefore, A matches with III.
• Myxine (B) - Hag fish (I): Myxine is the genus for hagfish, which are known for their slime-producing capability. Hence, B matches with I.
• Pristis (C) - Saw fish (II): Pristis is the genus comprising the sawfishes, which are known for their long, saw-like rostrums. Consequently, C matches with II.
• Exocoetus (D) - Flying fish (IV): Exocoetus is a genus of marine fish known as flying fish, due to their ability to glide above the water's surface for short distances. Therefore, D matches with IV.

Now, compiling these matches together:

• A - III
• B - I
• C - II
• D - IV

The correct option that matches each scientific name with their respective common names accordingly is: 
Option B: A-III, B-I, C-II, D-IV

Radial symmetry is a type of symmetry where an organism can be divided into similar halves by more than two planes passing through the central axis. This type of symmetry is found in organisms that tend to meet their environment in all directions, such as aquatic animals.

• Hemichordata : Adult organisms in this phylum, which includes acorn worms, pterobranchs, and graptolites, exhibit bilateral symmetry. This means they can be divided into two identical halves only along a single plane. Hence, radial symmetry is not found in the adults of this phylum.
• Coelenterata (also known as Cnidaria) : This phylum includes jellyfish, sea anemones, and corals. They exhibit radial symmetry. So, radial symmetry is found in this phylum.
• Echinodermata : Adult organisms in this phylum, which includes starfish, sea urchins, and sea cucumbers, exhibit radial symmetry. However, it's important to note that their larvae exhibit bilateral symmetry. Therefore, radial symmetry is found in adults of this phylum.
• Ctenophora (also known as comb jellies) : These marine animals also exhibit radial symmetry. Thus, radial symmetry is found in this phylum.

Unique mammalian characteristics include:

• Hair or fur: Mammals are the only animals that have hair. This hair helps to insulate the body to maintain a constant body temperature.
• Mammary glands: These are glands that, in females, produce milk for the nourishment of young ones. This is a characteristic feature of all mammals and is, in fact, the feature that gives this group its name.
• The presence of pinnae (external ears): Most mammals have pinnae that help to collect and direct sound waves into the ear.

Option A is incorrect because while mammals do have a tympanic membrane (ear drum), it is not unique to mammals; other vertebrate groups, such as birds and reptiles, also have a tympanic membrane.
Option C is incorrect because indirect development is not a unique characteristic of mammals; many animals, including certain insects, amphibians, and fishes, undergo indirect development.
Option D is incorrect because a monocondylic skull, in which the skull only articulates with the first vertebra via a single condyle, is a characteristic of some reptiles and amphibians, not mammals. Mammals possess a dicondylic skull, with two occipital condyles.
So, the correct answer is :
Option B : hairs, pinna and mammary glands.

Chordates are defined by having certain specific anatomical features at some point during their development. The correct attributes of chordates are:
1. Presence of a dorsal, hollow nerve cord (not a mid-dorsal, solid and double nerve cord as mentioned in statement A)
2. Presence of a closed circulatory system.
3. Presence of paired pharyngeal gill slits.
4. Presence of a post-anal tail.
5. Presence of a notochord.

Regarding the other statements :
- The heart of chordates is ventral, not dorsal (as in statement D).
- Chordates are triploblastic and coelomate, not pseudocoelomate (as in statement E).
So, based on these facts, the correct answer is :
Option B : B and C only.

Option (b) is the correct answer as chitin forms the exoskeleton is arthropods and is found in fungal cell wall. N-acetyl glucosamine is the monomeric unit. Cellulose is a polysaccharide. Cutin is a derived lipid.

All vertebrates are chordates because they possess a notochord at least at some time during their life. All chordates are not vertebrates because protochordates have notochord but lack a vertebral column. Therefore, A and R are true and R is the correct explanation of A.

• Option (4) is the correct answer because Chelone (turtle) is a reptile and the heart of reptiles are usually three-chambered except crocodiles.
• Option (1) is incorrect as Pteropus (flying fox) possess four -chambered heart.
• Option (2) and (3) are incorrect as Scoliodon (dog fish) and Hippocampus (sea horse) possess two - chambered heart.

Statement (a): They lack scales and paired fins.

• Analysis: This statement is correct. Cyclostomes, which include lampreys and hagfishes, do indeed lack scales and paired fins, which are common characteristics of these jawless fishes.

Statement (b): They have circular mouth with jaws.

• Analysis: This statement is incorrect. Cyclostomes have a circular mouth, but they do not have jaws; their mouth is instead adapted for sucking or latching onto prey.

Statement (c): They bear 6-15 pairs of gills.

• Analysis: This statement is correct. Cyclostomes have multiple pairs of gill pouches, which is typical for their respiratory system.

Statement (d): They migrate to deep sea for spawning.

• Analysis: This statement is incorrect. Cyclostomes, particularly lampreys, are known to migrate from the sea into freshwater rivers for spawning, not to the deep sea.

Conclusion: Based on the analysis, the incorrect statements are (b) "They have circular mouth with jaws." and (d) "They migrate to deep sea for spawning."

Therefore, the correct choice is: D. (b) and (d) only

• Those cnidarians which exist in both forms exhibit alternation of generation (Metagenesis), i.e., polyps produce medusae asexually and medusae form the polyps sexually (e.g., Obelia). Metagenesis is not observed in Helminths.
  Hence, statement a is incorrect.
• Comb Plates: Comb plates are a characteristic feature of ctenophores. They help in locomotion.
  Hence, statement d is incorrect.
• Roundworms: Roundworms belong to Phylum Aschelminthes and have organ-system level of body organisation.
  Hence, statement c is correct.
• Echinoderms: The echinoderms have three primary germ layers during development and hence are triploblastic. Echinoderms are coelomates as the cavity between the body wall and alimentary canal is lined by mesoderm. The most distinctive feature of echinoderms is the presence of water vascular system which helps in locomotion, capture and transport of food and respiration.
  Hence, statements b and e are correct.

Hence, The correct option is B 

NCERT Reference: Refer topics “4.2.2 Phylum – Coelenterata (Cnidaria)”, “4.2.3 Phylum – Ctenophora”, “4.2.5 Phylum – Aschelminthes” and “4.2.9 Phylum – Echinodermata”

The correct option is D: Platyhelminthes

• Flatworms are bilaterally symmetrical, triploblastic, and acoelomate animals with organ level of organisation.
• Aschelminthes is triploblastic, bilaterally symmetrical and pseudocoelomate.
• Annelida is triploblastic, bilaterally symmetrical and acoelomate.
• Ctenophora is radially symmetrical, diploblastic.

Hence, the correct option is D.
NCERT Reference: Page no. 51 of topic “4.2.4 Phylum – Platyhelminthes” of chapter 4.

Line in NCERT: "Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organisation."

• True segmentation is present in Annelida, Arthropoda and Chordata.
• They also have an organ-system level of organisation, bilateral symmetry and are true coelomates.
• On the other hand, molluscs have an unsegmented body.

Hence, the correct option is B.
NCERT Reference: Refer topics “4.2.6 Phylum – Annelida”, “4.2.7 Phylum – Arthropoda” and “4.2.11 Phylum – Chordata” of chapter 4.

Line in NCERT: "Animals with notochord are called chordates and those animals which do not form this structure are called non-chordates, e.g., porifera to echinoderms."

• Giving birth to living young that develop within the mother's body rather than hatching from eggs is called viviparity.
• All mammals except the monotremes are viviparous. Birds are oviparous and mammals are viviparous.

Hence, the correct option is C.

Similarities between Aves and Mammals are:

• Warm-blooded nature: Both are homeothermic (warm-blooded) animals they are able to maintain a constant body temperature.
• Both respire through the lungs.
• Ossified endoskeleton: An endoskeleton made of bones is known as an ossified endoskeleton. Most organisms like bony fishes, mammals, birds, and reptiles have an endoskeleton made purely out of bones and cartilage. In Aves endoskeleton is fully ossified (bony) and long bones are hollow with air cavities.
• Four-Chambered Heart: Both have a four-chambered heart.
• Fertilization: In both sexes are separate and fertilization is internal.

NCERT Reference: Refer topic “4.2.11.6 Class – Aves” and “4.2.11.7 Class – Mammalia” of chapter 4.

• Chondrichthyes always have a cartilaginous endoskeleton. Chondrichthyes is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone.
• Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas lay eggs.
• Chordates have jawless animals (Agnatha) as well.
• Most reptiles have 3 chambered heart. Crocodilians have 4 chambered hearts. Turtles have 3 chambered heart but with an incomplete wall in the single ventricle, so their hearts are functionally 4 chambered.

Hence, the correct option is A
NCERT Reference: Page no. 56 of topic “4.2.11.2 Class – Chondrichthyes” of chapter 4.

The correct option is A.

Explanation of correct option:

1. The phylum Porifera includes multicellular animals that are commonly called sponges. They exhibit the cellular level of organization; their body is a meshwork of cells.
2. Sponges possess a water transport system (canal) and an internal cavity (spongocoel).
3. The canal and spongocoel are lined by choanocytes (collar cells). Choanocytes are flagellated cells that help to filter water and food.
4. Sponges undergo indirect development. It is characterized by the presence of a larval stage which is morphologically different from the adult.

Explanation of incorrect option:

Option B:

1. The phylum Mollusca comprises bilaterally symmetrical and coelomate animals. Example: squid.
2. They are triploblastic and the level of organization is organ-system.

Option C:

1. Protozoans are eukaryotic, unicellular, and heterotrophs. Example: Amoeba.
2. They reproduce both sexually and asexually.

Option D:

1. The phylum Coelenterata (Cnidaria) includes aquatic animals that possess specialized cells called cnidoblasts. Example: corals.
2. They are diploblastic animals and exhibit tissue level of organization.

Final answer: Body having meshwork of cells, internal cavities lined with food filtering flagellated cells, and indirect development are the characteristics of phylum Porifera.

Hence, the correct option is A
NCERT Reference: Pge no. 49 of topic “4.2.1 Phylum – Porifera” of chapter 4.

Line in NCERT: "Sponges reproduce asexually by fragmentation and sexually by formation of gametes. Fertilisation is internal and development is indirect having a larval stage which is morphologically distinct from the adult."

The correct option is C

Explanation of correct option

1. Petromyzon marinus or sea lamprey is a jawless marine migratory fish that spends most of its adult life in the sea.
2. Matured fish migrate from marine to freshwater and lay eggs in areas with high oxygen levels.
3. These ammocoetes hatch and, before metamorphosis, migrate to the sea.

Explanation of incorrect option

Option A: 
Myxine glutinosa or Atlantic hagfish are non-migratory marine organisms without copulatory organs.

Option B:
Neomyxine biniplicata or hagfishes are non-migratory marine organisms without copulatory organs.

Option D:
Eptatretus stoutii or Pacific hagfish are non-migratory marine organisms without copulatory organs.

Final answer: A jawless fish that lays eggs in freshwater and whose ammocoetes larvae after metamorphosis return to the ocean is Petromyzon.

NCERT Reference: Page no. 56 of topic “4.2.11.1 Class – Cyclostomata” of chapter 4.

Line in NCERT: "Cyclostomes are marine but migrate for spawning to fresh water. After spawning, within a few days, they die. Their larvae, after metamorphosis, return to the ocean. Examples: Petromyzon (Lamprey) and Myxine (Hagfish)."

• Animals that give birth to offspring are called viviparous.
• Platypus is an oviparous animal (egg-laying). It belongs to the class- Mammalia. The platypus (Ornithorhynchus anatinus), also known as the duck-billed platypus, is a semiaquatic egg-laying monotreme.
• Elephant, Whale and Flying fox are viviparous animals. All mammals are viviparous except monotremes. It is the only mammals that lay eggs instead of giving birth to live young.

Hence, the correct option is B.
NCERT Reference: Page no. 60 of topic “4.2.11.7 Class – Mammalia” of chapter 4.

• Cnidarians are aquatic, mostly marine, solitary or colonial sessile or free-swimming radially symmetry animals while members of Ctenophora, Cephalochordata, Echinodermata are found exclusively in the marine environment.

So the correct answer is 'Cnidaria'.

Hence, the correct option is D.
NCERT Reference: Page no. 50 of topic “4.2.2 Phylum – Coelenterata (Cnidaria)” of chapter 4,

• Planaria is a flatworm that possesses a high power of regeneration due to the neoplastic cells which are found in them.
• If an individual is cut transversely into two parts, the anterior segment will generate a new tail and the posterior end will develop a new head.

Hence, the correct option is B.
NCERT Reference: Page no. 51 of topic “4.2.4 Phylum – Platyhelminthes” of chapter 4.

Line in NCERT: "Some members like Planaria possess high regeneration capacity."

• Torpedo is electric ray. Torpedo is a sluggish fish. It is carnivorous. The prey is firstly killed by electric shock. The shock can also be harmful to human beings.
• Pristis is a sawfish.
• Trygon is sting ray
• Scoliodon is a dog fish.

Hence, the correct option is B.

Topic in NCERT: Class - Chondrichthyes

Line in NCERT: "Some of them have electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon)."

• Cyclostomata have sucking and circular mouth without jaws. Median fins (appendages) are present but paired fins (appendages) are absent. Integuments are without scales.
•  In aves, forelimbs are modified into wings for flying and hind limbs are used for walking and running. The body is covered with feathers. Skin is thin, dry and non-glandular. Lungs have air sacs. 
• In mammals, mammary glands are present for the nourishment of the young ones. Hairs are present on the body. They have 2 pairs of limbs. Pinnae are absent in monotreme (mammals that lay eggs). 
• Chondrichthyes have a persistent notochord, placoid scales as the exoskeleton and ventrally positioned mouth. Gill slits are not covered by an operculum. 

Hence, the correct option is A.
NCERT Reference: Page no. 56 of topic “4.2.11.2 Class – Chondrichthyes” of chapter 4.

• Parapodia are present in aquatic annelids like Nereis, which help them in swimming.
• The other three features, i.e. metameric segmentation, jointed appendages and chitinous exoskeleton are present in phylum-Arthropoda. 

Hence, the correct option is C
NCERT Reference: Page no. 52 of topic “4.2.6 Phylum – Annelida” of chapter 4.

Line in NCERT: "The body of arthropods is covered by chitinous exoskeleton."