All Free Biology MCQs with Answers

1201. The skeleton of the sponges is in the form of variously shaped needle like structures called___________?

• A. Stripules
• B. Spicules
• C. Brails
• D. Spines

Explanation: Sponges commonly contain mineral or organic needle-like skeletal elements called spicules, which provide support and protection. Students may choose d because spines are also pointed structures, but spines are not the standard skeletal term for Porifera.

1202. The internal buds are known as__________?

• A. Spicules
• B. Choanocytes
• C. Gemmules
• D. None of these

Explanation: Freshwater sponges produce resistant internal buds called gemmules, which help them survive unfavorable conditions and later develop into new sponges. Students may choose a because gemmules may contain spicules, but spicules are skeletal structures rather than buds.

1203. Venus flower basket is also known as___________?

• A. Sycon
• B. Euplectella
• C. Leucoselenia
• D. Spongilla

Explanation: The Venus flower basket is Euplectella, a glass sponge with a delicate lattice-like skeleton. Students may choose a because Sycon is also a sponge, but Sycon is the smaller urn-shaped calcareous sponge commonly called Scypha.

1204. In acoelomates gut is ________ in origin.

• A. Ectodermal
• B. Endodermal
• C. Mesodermal
• D. None of these

Explanation: In acoelomate animals, the digestive tract is an endodermal structure, while mesoderm fills the region between the gut and body wall. Students may choose c because mesoderm occupies much of the interior, but it does not form the gut lining.

1205. The fate of each blastomere is foretold. The cleavage will be as____________?

• A. Spiral and indeterminate
• B. Radial and indeterminate
• C. Radial and indeterminate
• D. Spiral and determinate

Explanation: Protostomes typically show spiral, determinate cleavage, meaning the fate of each early blastomere is largely fixed. Students may choose a because it includes spiral cleavage, but indeterminate cleavage is characteristic of radial deuterostome development rather than the stated pattern.

1206. All the animals of the grade radiata are____________?

• A. Diploblastic
• B. Triploblastic
• C. Both
• D. Unicellular

Explanation: Radiate animals such as cnidarians develop from two primary germ layers, ectoderm and endoderm, so they are diploblastic. Students may choose c because some organisms show unusual developmental features, but the standard radiata group is classified as diploblastic.

1207. The name animal is derived from the word__________?

• A. Anima
• B. Anemia
• C. Aname
• D. All of these

Explanation: The word animal comes from the Latin anima, meaning breath, soul or living principle. Students may choose b because anemia begins with similar letters, but anemia is a medical condition involving reduced oxygen-carrying capacity and is unrelated to the word's origin.

1208. Shell of egg is leathery in appearance in___________?

• A. Amphibians
• B. Reptiles
• C. Birds
• D. Prototherians

Explanation: Reptile eggs usually have a tough, flexible, leathery shell that reduces water loss while allowing some exchange of gases. Students may choose c because bird eggs also have shells, but bird shells are typically hard and heavily calcified rather than leathery.

1209. Circulatory system is open type in all of the following except:___________?

• A. Arthropoda
• B. Gastropoda
• C. Pelecypoda
• D. Cephalopoda

Explanation: Arthropods, gastropods and pelecypods generally have open circulation, but cephalopods have a closed circulatory system in which blood remains within vessels. Students may choose b because gastropods can have more specialized circulation, but their system is still open.

1210. Of the following which one is non-cellular in most cases in animals?

• A. Mesenchyme
• B. Sclerenchyma
• C. Chlorenchyma
• D. Mesoderm

Explanation: Mesenchyme is a loose, gelatinous supporting material that may be largely non-cellular in simple animals such as sponges, although mesenchyme in higher animals contains cells. Students may choose b because mature sclerenchyma cells are dead and lack protoplasm, but sclerenchyma is a plant tissue, not an animal tissue.