Animal Kingdom - NEET Biology Class 11 Free MCQ Test with solutions

• Annelids are triploblastic (three germ layers present) and possess a true coelom.
• The coelom is the fluid-filled body cavity present between the gut wall and body wall.
• Some of the examples of annelids are earthworms, leeches, etc.

Hence, the correct option is B.
NCERT Reference: Topic  Phylum – Annelida” of chapter Animal Kingdom

• Symmetry is an attribute of an organism showing regularity in body parts on a plane or around an axis.
• In Phylum Echinodermata, the adult echinoderms are radially symmetrical but the larvae are bilaterally symmetrical. 

Hence, the correct option is B.

NCERT Reference: Topic: Phylum – Echinodermata” of chapter Animal Kingdom

• The insects belong to phylum Arthropoda and hence, the excretory organ is Malpighian tubules.
• Malpighian tubules are the main excretory organs in insects. They are a part of the insect digestive system and play a crucial role in maintaining the insect's internal balance of water and ions, as well as in excreting waste products from the body.

Hence, the correct option is B.

NCERT Reference: Topic “Phylum – Arthropoda” of chapter Animal Kingdom.

To evaluate the given assertion and reason, let's analyze each statement individually and then determine their relationship.

Assertion (A): Nematodes are pseudocoelomates.

Nematodes, also known as roundworms, are indeed pseudocoelomates. This means they have a body cavity that is not fully lined with mesodermal tissue.

Reason (R): Pseudocoelomates have a body cavity that is not fully lined with mesoderm.

This statement is correct. Pseudocoelomates have a body cavity called a pseudocoelom, which is only partially lined with mesoderm. In contrast, coelomates have a body cavity completely lined with mesoderm.

Now, let's determine if the reason correctly explains the assertion. The assertion states that nematodes are pseudocoelomates, and the reason provides a correct definition of what pseudocoelomates are.

Therefore, both the assertion and the reason are correct, and the reason correctly explains the assertion.

So, the correct answer is:

  4. Both (A) and (R) are true, and (R) is the correct explanation of (A).

The members of class Chondrichthyes are marine animals with streamlined body and have cartilaginous endoskeleton.

• Option D, Chondrichthyes are a class of fish that includes species such as sharks, rays, and skates. One of the defining characteristics of Chondrichthyes is that they possess a skeleton made of cartilage, which is a flexible and lightweight material, as opposed to the bony skeleton found in most other vertebrates, including mammals, reptiles, and chordates.
• Option A, Reptilia possess a 3-chambered heart with incompletely divided ventricle, is not a correct answer as reptiles, such as snakes, lizards, and turtles, generally possess a 3-chambered heart with a partially divided ventricle, which allows mixing of oxygenated and deoxygenated blood. However, there are some exceptions among reptiles, such as crocodiles, which possess a 4-chambered heart with completely divided ventricles.
• Option B, Mammalia give birth to young ones, is not a correct answer as there are some mammals, such as monotremes like platypus and echidna, that lay eggs instead of giving birth to live young.
• Option C, Chordates possess a mouth with an upper and lower jaw, is not a correct answer as not all chordates possess jaws. Jawless fish, such as lampreys and hagfish, which are also chordates, do not possess jaws.

Hence, the correct option is D.
NCERT Reference:  Topic : Class – Chondrichthyes” of chapter  Animal Kingdom

• Air bladder provides buoyancy to the aquatic animals thus helps them to stay at the current water depth without having to waste energy in swimming.
• It is found in many bony fishes but not in cartilaginous fishes. Shark being a cartilaginous fish, does not possess air bladder.

Hence, the correct option is B.
NCERT Reference: topic: Class – Chondrichthyes of chapter Animal Kingdom

Radula is  a tongue-like structure with tiny teeth that helps molluscs scrape and shred their food for consumption.
This feature is a distinctive characteristic of molluscs and plays a crucial role in their feeding process.

Hence, the correct option is A.

NCERT Reference: Topic  Phylum – Mollusca” of chapter Animal Kingdom

In Urochordata, the notochord is present only in the larval tail, while in Cephalochordata, it extends from head to tail region and is persistent throughout their life.

Euspongia, which belongs to the phylum Porifera, is commonly known as a sponge. Sponges are some of the simplest and most primitive animals in the animal kingdom.

Hence, the correct option is C.
NCERT Reference: Topic: Phylum – Porifera” of chapter Animal Kingdom

It is true that all echinoderms, including starfish, sea urchins, and sea cucumbers, are found exclusively in marine environments. The reason correctly explains that the water vascular system, a hallmark of the echinoderm body plan, is indeed adapted to marine life.

• It has three-layered body wall which includes ectoderm, endoderm, and mesoderm. 
• Acoelomates lack a body cavity, and instead the space between the body wall and the digestive tract is filled with muscle fibres and loose tissue called parenchyma.
• It acts as a skeletal support, nutrient storage, motility, reserves of regenerative cells and transporting materials.
• Planaria belongs to phylum Platyhelminthes.
• These are flatworms and has acoelomate body plan.

Hence, the correct option is D.

NCERT Reference: Topic Phylum – Platyhelminthes” of chapter Animal Kingdom
 

Class-Cyclostomata is comprised of  the living jawless fishes. Their mouth is circular and lack jaws, hence they are also called agnathans.  It is surrounded by tentacles (e.g., lampreys and hagfish). These also possess retractable teeth.

Hence, the correct option is B.
NCERT Reference: Topic: Class – Cyclostomata” of chapter Animal Kingdom

Saccoglossus is an organism that belongs to the phylum Hemichordata. The phylum Hemichordata includes marine animals known as acorn worms, and one of the distinctive features of these organisms is the presence of a unique excretory organ known as the proboscis gland.

NCERT Reference: Topic: Phylum – Hemichordata” of chapter Animal Kingdom

• Tissue level of organization is present in Coelenterata.
• Sea anemone is solitary, while corals are colonial.
• Coelenterates have two layers of cells in their body i.e. they are diploblastic.
• They have an incomplete digestive system.

Hence, the correct option is D.
NCERT Reference: Topic: Phylum – Coelenterata (Cnidaria)” of chapter Animal Kingdom

Flame cells are specialized cells in flatworms that help in osmoregulation and excretion by regulating the balance of fluids and salts in their bodies.

Platypus is oviparous as it is an egg-laying mammal. Rest three are viviparous mammals.

Hence, the correct option is A.
NCERT Reference: Topic: Class – Mammalia” of chapter Animal Kingdom

Reptiles generally possess three chambered heart, two upper chamber (atria) and single lower chamber (ventricle). But in crocodile, the heart is four chambered having two atrium and two ventricles.

Hence, the correct option is C.
NCERT Reference: Topic: Class – Reptilia of chapter Animal Kingdom

The correct option is D (1)-(iii), (2)-(iv), (3)-(i), (4)-(ii)
Ophiura belong to phylum echinodermata. These animals have an endoskeleton of calcareous ossicles and, hence, the name Echinodermata (spiny bodied). All are marine with organ-system level of organisation. The adult echinoderms are radially symmetrical but larvae are bilaterally symmetrical. They are triploblastic and coelomate animals.

Physalia (Portuguese man of war) belongs to phylum coelenterata. They are aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals. The name Cnidaria is derived from the cnidoblasts or cnidocytes (which contain stinging capsules or nematocytes) present on the tentacles and the body. Cnidoblasts are used for anchorage, defense and for the capture of prey. Cnidarians exhibit tissue level of organisation and are diploblastic.

Pinctada (pearl oyster) belongs to phylum mollusca. This is the second largest animal phylum. Molluscs are terrestrial or aquatic (marine or fresh water) having an organ-system level of organisation. They are bilaterally symmetrical, triploblastic and coelomate animals.

Planaria which possess high regeneration capacity belongs to from phylum platyhelminthes. They have dorso-ventrally flattened body, hence are called flatworms. These are mostly endoparasites found in animals including human beings. Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organisation.

Aptenodytes is a genus of penguins, so it matches with (iv) Penguin.
Pteropus refers to a genus of flying foxes, so it matches with (i) Flying fox.
Pterophyllum is a genus of angelfish, so it matches with (ii) Angel fish.
Petromyzon is a genus of lampreys, so it matches with (iii) Lamprey.
Thus, the correct option is Option C: (iv), (i), (ii), (iii).

Placoid Scales are characteristic of Chondrichthyes (cartilaginous fishes).
Ctenoid Scales are characteristic of Osteichthyes (bony fishes).
Ectoparasites are typically associated with Cyclostomata (e.g., lampreys).
Proboscis gland is a feature of Hemichordata (e.g., acorn worms).
Thus, the correct code is Option D: 1 2 4 3.

i) Spider and mosquito possess compound eye: This is incorrect. Mosquitoes (insects) have compound eyes, but spiders (arachnids) do not—they typically have simple eyes (ocelli). Compound eyes are characteristic of insects and some crustaceans, not spiders.
ii) Jelly fishes possess cnidoblasts but comb-jellies lack them: This is correct. Jellyfish (phylum Cnidaria) have cnidoblasts (stinging cells with nematocysts) used for defense and prey capture. Comb-jellies (phylum Ctenophora) lack cnidoblasts and instead use colloblasts (sticky cells) to catch prey.
iii) All animals having true coelom are characterized by the presence of bilateral symmetry usually, tube-within-tube body plan, presence of mesoderm and true segmentation: This is partially correct but misleading. Animals with a true coelom (coelomates) do have a mesoderm-lined body cavity and often exhibit bilateral symmetry and a tube-within-tube body plan (e.g., annelids, arthropods, chordates). However, "true segmentation" is not a universal feature of all coelomates—it’s specific to certain groups like annelids and chordates, but not all (e.g., mollusks lack true segmentation). The word "usually" makes this statement debatable, but it’s not entirely accurate as written.
iv) The animals of the phylum Porifera have originated from colonial protozoans: This is correct. Sponges (phylum Porifera) are widely believed to have evolved from colonial protozoans, such as choanoflagellates, based on similarities in their choanocyte cells and simple multicellular organization.

(i) True coelom is a body cavity which arises as a cavity in the embryonic mesoderm.
Correct — A true coelom is completely lined by mesoderm and develops within the mesoderm.

(ii) Digestive cavity is found in acoelomates, pseudocoelomates as well as coelomates.
Correct — The alimentary canal (digestive cavity) is present in all three groups.

(iii) The body cavity of arthropods and non-cephalopod molluscs is called haemocoel.
 Correct — In these animals, the true coelom is reduced and the main body cavity is a haemocoel filled with blood.

(iv) Aschelminthes possess true body cavity.
 Incorrect — Aschelminthes (Nematodes) are pseudocoelomates, not true coelomates.

(v) There is no cavity between the body wall and gut in Echinoderms.
 Incorrect — Echinoderms are true coelomates and possess a coelomic cavity.

Correct Answer: b) (i), (ii), (iii)