The frog is considered a better swimmer than the toad because it

A. has more pronounced webbed digits

B. has much longer and stronger hind limbs

C. lives in water most of the time

D. is more streamlined than the toad

The bacteria that reduce nitrates in the soil into gaseous nitrogen are referred to as

A. nitrifying bacteria

B. denitrifying bacteria

C. putrefying bacteria

D. saprophytic bacteria

A pyramid of numbers is constructed by

A. comparing living and non-living things

B. measuring productivity

C. conducting census

D. labelling the living organisms

The main reason for immunizing children is to

A. destroy pathogens in their bodies

B. increase the production of white blood cells

C. stimulate the production of antibodies

D. simulate the production of antigens

Rhizobium which lives in the root nodules of leguminous plants is an example of the association known as

A. commensalism

B. epiphytism

C. mutualism

D. saprophytism

Ascaris lumbricoides is a parasitic

A. flat worm

B. round worm

C. arthropod

D. elastic worm

The following organisms are pests of plants except

A. birds

B. nematodes

C. bacteria

D. rodents

The absence of alimentary canal in the parasitic flatworm can be attributed to the fact that

A. its body does not feed

B. it has no enzymes

C. its body absorbs digested food

D. it has suckers on the scolex

Which of the following human activities would help prevent endangered species from extinction?

A. Uncontrolled killing of species

B. Regular clearing of the forest vegetation

C. Temporary maintenance of species in zoological gardens

D. Regular irrigation of their natural habitats

Which of the following statements is not a reason for conserving wildlife?

A. Attraction of tourists into the country

B. Serving as a source of food

C. Serving as a source of income

D. increasing the amount of rainfall