Free Biodiversity and Variety of Life MCQs with Answers

1331. Which statement is correct about cnidarians?

• A. They kill the prey with the help of stinging cells
• B. They kill the prey with the help of tentacles
• C. They kill the prey with the help of spicules
• D. They kill the prey with the help of barbs

Explanation: They kill the prey with the help of stinging cells - Correct. Cnidarians have specialized stinging cells (nematocysts) in their tentacles that help immobilize prey.

1332. What are the true characteristics of class Anthozoa?

• A. Mesoglea fibrous, predominantly medusoid
• B. Mesoglea cellular, both polyp & medusa
• C. Mesoglea fibrous, polypoid forms only
• D. Mesoglea, non-cellular, polypoids form

Explanation: Mesoglea fibrous, polypoid forms only - Correct. Class Anthozoa includes organisms such as corals and sea anemones, which exist only in the polyp stage.

1333. Common characteristics of Hirudinaria are:1. Setae & parapodia absent 2. Setae are present but parapodia absent 3. Blood suckers are present

• A. 1, 2 & 3
• B. 1 & 3
• C. 1 & 2
• D. 2 & 3

Explanation: 1 & 3 - Correct. Hirudinaria (a genus of leeches) lacks setae and parapodia and is a blood-sucking annelid.

1334. The flatworm that is the endoparasite of humans:

• A. Dugesia
• B. Fasciola
• C. Taenia
• D. Hydra

Explanation: Taenia - Correct. Taenia (tapeworm) is an endoparasite that resides in the human intestines.

1335. Which of the following represents order of 'Horse'?

• A. Perissodactyla
• B. Caballus
• C. Ferus
• D. Equidae

Explanation: Horses belong to the order Perissodactyla, which is a group of mammals characterized by an odd number of toes on their hind feet. Horses, along with other animals like zebras and rhinoceroses, are considered perissodactyls because they typically have one hoofed toe (a single large toe) on each foot. This distinguishes them from the even-toed ungulates (Artiodactyla), such as cows, deer, and pigs, which have an even number of toes on their hind feet.

1336. Metagenesis refers to:

• A. Occurrence of a drastic change in form during postembryonic development
• B. Presence of a segmented body and parthenogenetic mode of reproduction
• C. Presence of different morphic forms
• D. Alternation of generation between asexual and sexual phases of an organism

Explanation: An alternation of generation between asexual and sexual phases of an organism is referred to as metagenesis. E.g. in Obelia (a coelenterate), polyps reproduce asexually and medusae reproduce sexually.

1337. Pheretima and its close relatives derive nourishment from:

• A. Sugarcane roots
• B. Decaying fallen leaves and soil organic matter
• C. Soil insects
• D. Small pieces of fresh fallen leaves of maize, etc

Explanation: The correct answer is that Pheretima and its close relatives derive nourishment from decaying fallen leaves and soil organic matter. Earthworms, including those in the Pheretima genus, are detritivores; they play a role in breaking down and recycling dead plant material, thus improving soil structure and fertility. Other options such as sugarcane roots, soil insects, and fresh leaves do not accurately represent their diet. Earthworms are not equipped to consume live plant roots or soil insects, and fresh leaves are not their primary food source as they prefer decomposed material for easier digestion.

1338. The figures (A - D) show four animals. Select the correct option with respect to a common characteristic of two of these animals.

• A. (A) and (D) respire mainly through body wall
• B. (B) and (C) show radial symmetry
• C. (A and (B) have cnidoblasts for self defence
• D. (C) and (D) have a true coelom

Explanation: The animals which possess true coelom are called eucoelomates or coelomates. The true coelom is a body cavity which arises as a cavity in embryonic mesoderm. True coelom is of two types; schizocoelom (schizocoel) and enterocoelom (enterocoel). Schizocoelom develops as a split in the mesoderm sheet. It is found in annelids, arthropods, molluscs. In enterocoelom, mesoderm arises from the wall of the embryonic cut of enteron as hollow outgrowths. It occurs in echinoderms and chordates.

1339. All animals having a single opening to the outside that serves both as mouth as well as anus except?

• A. Octopus
• B. Asterias
• C. Ascidia
• D. Fasciola

Explanation: Octopuses do not have a single external opening for both ingestion and egestion. Octopuses have a more complex digestive system compared to some other animals. They have separate openings for ingestion and egestion.

1340. All of the following organisms are its excretory organs correctly stated except?

• A. Humans - Kidneys, sebaceous glands and tear glands
• B. Earthworm - Pharyngeal, integumentary and septal nephridia
• C. Cockroach - Malpighian tubules and enteric caeca
• D. Frog - Kidneys, skin and buccal epithelium

Explanation: Kidneys are the primary excretory organs in humans. They filter waste products and excess substances from the blood to form urine, which is then eliminated from the body. Sebaceous glands and tear glands do not serve as excretory organs; they have different functions related to skin and eye health, respectively.