Free Biodiversity and Variety of Life MCQs with Answers

881. In acoelomates, gut is lined externally by:

• A. Visceral mesoderm
• B. Parietal mesoderm
• C. Splanchine mesoderm
• D. Endoderm

Explanation: The visceral mesoderm is a layer of the mesoderm in embryonic development that surrounds and supports the internal organs or viscera, including the heart, lungs, and digestive organs. It plays a vital role in the formation and development of these organs during embryogenesis, providing structural and functional support to ensure proper organ function.

882. Which system is more developed in acoelomates?

• A. Excretory system
• B. Respiratory system
• C. Digestive system
• D. Osmoregulatory system

Explanation: Acoelomate has sac type digestive system, no respiratory and osmoregulatory systems. They have tubular excretory system called protonephridia having flame cells.

883. Spiral and determinate type cleavage is present in:

• A. Pinworm
• B. Star fish
• C. Cake urchin
• D. Amphioxus

Explanation: Spiral and determinate type cleavage is present in proterostomes. Pinworm belongs to phylum. Aschelminthes that are proterostomes

884. Indeterminate cleavage is not a characteristic of:

• A. Echinodermata
• B. Mollusca
• C. Chordata
• D. Hemichordata

Explanation: Molluscs are proterostomes and have determinate cleavage in which fate of blastomeres is foretold. Indeterminate cleavage is characteristic of deuterostomes.

885. It is not true for Phylum Platyhelminthes:

• A. Bilaterally symmetrical
• B. Triploblastic metazoan
• C. Dorsoventrally compressel body
• D. Radially symmarical body

Explanation: Phylum Platyhelminthes have bilateral symmetry. This means there is only one plane of symmetry.

886. The body of Aschelminthes is covered by a hard layer of:

• A. Chitin
• B. Cuticle
• C. Cilia
• D. Spongin

Explanation: Intestinal parasites, generally do not absorb nutrients through the body surface as there is usually a thick cuticle to protect themselves from the host's digestive liquids.

887. The nervous system in Aschelninthes consists of a nerve ring that encircles the following:

• A. Mouth
• B. Pharynx
• C. Laynx
• D. Anus

Explanation: The nematode nervous system consists of a set of neuronal processes that run lengthwise on the nematode body. These processes consist of neurons that have a cell body also known as a neurocyte. A group of neurocytes is called a ganglion. These ganglion connect to the nerve ring which surrounds the Pharynx.

888. Locomotary organs are_in earthworms and_in Neries respectively.

• A. Setae, parapodia
• B. Parapodia, setae
• C. Setae
• D. Setae, chaetae

Explanation: Locomotary setae are for crawling and are the bristles that are visible on the exterior of the earthworm. Slow creeping movements of Neries are carried out by the action of parapodia only.

889. The most successful group and the largest phylum of the animals:

• A. Phylum Mollusca
• B. Phylum Porifera
• C. Phylum Annelida
• D. Phylum Arthropoda

Explanation: More than 50% of total biodiversity of our planet is formed by the Arthropods.

890. Natural silk is not:

• A. A protein
• B. Produced by modified salivary glands
• C. Obtained from an insect
• D. Glycolipid in nature

Explanation: Natural silk is fibrous protein produced by larvae of silk worm.