Free Biodiversity and Variety of Life MCQs with Answers

811. Which of the following is an example of platyhelminthes?

• A. Plasmodium
• B. Schistosoma
• C. Trypanosoma
• D. Wuchereria

Explanation: Platyhelminthes have soft and dorsoventrally flattened body with bilateral symmetry. Plasmodium and Trypanosoma belong to Phylum Protozoa while Wuchereria belongs to Phylum Aschelminthes.

812. Among the following organisms point out a completely non-parasitic form.

• A. Tape worm
• B. Mosquito
• C. sea anemone
• D. leech

Explanation: Sea anemone is a completely non-parasitic form. It shows the example of mutualism. Sea anemone attaches itself to shell of a hermit crab. The anemone obtains nourishment from the scraps of food left by the crab, and is transported from place to place when the crab moves. The crab is protected by the stinging cells in the tentacles of the sea anemone. Mosquito and leech are parasites of animals and feed on their blood. Tapeworm is a human gut parasite.

813. Tube feet are the characteristic structures of:

• A. starfish
• B. Jellyfish
• C. Crayfish
• D. Cuttlefish

Explanation: Starfish belongs to the phylum echinodermata who have developed tube feet for locomotion. The tube feet generally protrude out through special radial areas called ambulacra. They are extended and retracted by variations in hydraulic pressure of fluid in them and by contractions of their muscles. Cuttle fish belongs to the Phylum Mollusca and it swims. Crayfish belongs to the Phylum Arthropoda in which locomotion occurs by jointed appendages. Jelly fish belongs to the Phylum Cnidaria and it swims.

814. Two examples in which the nitrogenous wastes are excreted from the body in the form of uric acid are:

• A. Birds and lizards
• B. Frogs and cartilaginous fish
• C. Insects and bony fish
• D. mammals and molluscs

Explanation: Birds and lizards are uricotelic. Uricotelic animals are those that excrete nitrogenous waste in the form of uric acid. Being insoluble in water, uric acid does not require water for its elimination.

815. Which of the following does not have an open circulatory system?

• A. Frog's tadpole
• B. Prawn
• C. Chelifer
• D. Cockroach

Explanation: In the open circulatory system, the blood is not confined to the blood vessels, but it flows in the open spaces. Prawn, Chelifer and cockroach have open circulatory systems. Frog's tadpole has a closed circulatory system, that is the blood flows in the blood vessels.

816. The ostrich, penguin and kiwi are _

• A. Running birds
• B. Migratory birds
• C. Flightless birds
• D. Four toed birds
• E. A and c

Explanation: The ostrich is a flightless bird native to Africa. It is the only living species of its family. It is distinctive in its appearance, with a long neck and legs and the ability to run at speeds of about 65 km/h (40 mph), the top land speed of any bird. Penguins are a group of aquatic, flightless birds living almost exclusively in the Southern Hemisphere. A kiwi is any of the species of small flightless birds endemic to New Zealand.

817. Which of the following assists in locomotion?

• A. Trichocyst in Paramecium
• B. Pedicellariae of star fish
• C. Clitellum in Pheretima
• D. Posterior sucker in Hirudinaria

Explanation: The looping or crawling movement in Hirudinaria is performed with the help of muscles and suckers which serve for attachment.

818. Which one of the following animals possesses nerve cells but no nerves?

• A. Hydra
• B. Tapeworm
• C. Earthworm
• D. Frog's tadpole

Explanation: Hydra possesses a very primitive type of nervous system. It includes bipolar and multipolar nerve cells or neurones lying immediately above the muscle processes and forming an irregular and discontinuous nerve net or nerve plexus. Neighbouring nerve cells are not fused together, but their processes or neurites form synaptic junctions. Such a nerve net is called a synaptic nerve net. Nerve cells are numerous around mouth and on pedal disc but show no groupings in the form of a nerve controlling centre like brain or nerve ring. A difference from higher animals is that the nerve net of Hydra is unpolarized so that impulses can pass in all directions (diffuse transmission). In brief, nerve net shows diffuse unpolarized transmission, autonomy of parts and paucity of reflexes.

819. Budding is a normal mode of asexual reproduction in:

• A. Starfish and Hydra
• B. Hydra and sponges
• C. Tapeworm and Hydra
• D. Sponge and starfish

Explanation: Budding is an asexual mode of reproduction in Hydra and sponges. Buds are formed as outgrowths on the body surface and then detached to form new animals

820. Tracheae of cockroach and mammal are similar in having:

• A. Paried nature
• B. Noncollapsible walls
• C. Ciliated inner lining
• D. Origin from head

Explanation: Tracheae act as passage of air during respiration in both cockroach and mammals. In cockroach, the cuticular lining is spirally thickened forming taenidia which prevents the tracheal tubes from collapsing. In mammals, cartilaginous rings supporting the walls of the tracheae prevent their collapsing.