Free Biodiversity and Variety of Life MCQs with Answers

3001. Which of the following animal is included in protostome?

• A. Sea horse
• B. Sea mouse
• C. Sea cucumber
• D. Sea lion

Explanation: Annelids, Molluscs, and arthropods fall into the category of protostomes. Sea mice belong to the phylum annelida, therefore they are protostomes.Sea lions, and sea horses are chordates, whereas sea cucumbers are echinoderms.Protostomes are organisms in which blastopore develops into the mouth. These include phylums Annelida, Arthropoda, Mollusca.Deuterostomes are organisms in which blastopore develops into anus first and later into mouth. These include phylums Echinodermata, Hemichordate, Chordata.

3002. How many waling legs are present in arachnids?

• A. 4
• B. 6
• C. 8
• D. 10

Explanation: Arachnids(spider-like) is a class of Phylum Arthropoda with 4 pairs of legs, so a total of 8 legs.

3003. In octopus, the foot is modified into:

• A. Disc
• B. Arm
• C. Foot
• D. Siphon

Explanation: The muscular foot has been modified in cephalopods (Octopus) to form the tentacles and the siphon.The siphon is the tubular portion of the octopus that can draw water in and out of its body using its muscular mantle. This action allows oxygenated water to flow over its internal gills so that it can breathe.

3004. Which of the following is included in deuterestome?

• A. Brittle star
• B. Scorpion
• C. Chaetopterus
• D. Unio

Explanation: Brittle Stars are Echinoderms which are marine animals having radial symmetry with five parts, often with spines. So it is a deuterostome. Deuterostomia are animals typically characterized by their anus forming before their mouth during embryonic development.

3005. Which of the following fish have 14 pairs of gill slits?

• A. Dogfish
• B. Lamprey
• C. Catfish
• D. Ray fish

Explanation: Maximum number of gill slits present in cyclostomes . Cyclostomes have 6-15 pairs of gills. Lampreys are example of cyclostomes.

3006. In which of the following, does the pharynx opens directly into the intestine?

• A. Planaria
• B. Earthworm
• C. Cockroach
• D. Snail

Explanation: In planaria, the mouth opens into muscular tubular pharynx which leads into the intestine.

3007. Coelentrates have hydrostatic skeletion except:

• A. Coral
• B. Sea anemone
• C. Hydra
• D. Jellyfish

Explanation: Corals are unique among coelenterates because they secrete a hard exoskeleton made of calcium carbonate (CaCO3), which is distinct from the hydrostatic skeleton found in other coelenterates like sea anemones, hydras, and jellyfish. These other organisms use fluid pressure within their bodies to maintain shape and support movement. Thus, corals are the exception to the typical hydrostatic skeleton seen in this group.

3008. A complex form of learning that requires the manipulation of mental concepts to arrive at adaptive behavior is:

• A. Imprinting
• B. Insight learning
• C. Latent learning
• D. Trial & error learning

Explanation: The complex form of learning that requires the manipulation of mental concepts for developing an adaptive behaviour is called insight learning.

3009. All of the following are triploblastic animals except:

• A. Annelida
• B. Mollusca
• C. Coelenterata
• D. Echinodermata

Explanation: Phylum Coelenterata is a group of aquatic and marine organisms with a radially symmetrical body. They are diploblastic organisms in which the body is made up of two embryonic layers i.e. ectoderm and endoderm.

3010. Hermaphrodite phylum is:

• A. Annelida
• B. Arthropoda
• C. Echinodermata
• D. Mollusca

Explanation: A hermaphrodite is an organism with both male and female reproductive organs. Annelids are mostly hermaphroditic, making option A the correct answer. Arthropods, echinoderms, and mollusks generally have separate sexes, with only some exceptions showing hermaphroditism.