WAEC Biology Past Questions & Answers - Page 79

391.

An association between living organisms in which one lives on and feeds at the expense of the other is known as

A.

commensalism

B.

predation

C.

parasitism

D.

mutualism

Correct answer is C

A parasite is an organism that lives on or in a host organism and gets its food at the expense of its host.

392.

Xerophytes have the following characteristics aimed at conserving water except

A.

thick cuticle

B.

broad leaf surfaces

C.

sunken stomata

D.

waxy cuticle

Correct answer is B

The xerophytes have reduced leaf size in order to reduce the surface area, thereby reducing the water loss in the plant.

393.

In an ecosystem, the least efficient energy transfer link is from the

A.

secondary consumers to decomposers

B.

sun to producers

C.

primary consumers to secondary consumers

D.

producer to primary consumers

Correct answer is A

From the food chain, the energy flows from the producers to the primary consumer to the secondary consumers and about 90% of the energy is lost in the process of this transfer. Hence, the energy level by the time it gets to the secondary consumers. There is less energy transferred to the decomposers.

394.

Which of the following instruments is used to determine the turbidity of water?

A.

hygrometer

B.

hydrometer

C.

secchi disc

D.

rain gauge

Correct answer is C

The secchi disc is used to check for the transparency and the turbidity of water.

395.

The diagram above is an illustration of organisms in an air-tight aquarium.The most important factor needed by the organisms is

A.

light energy

B.

low humidity

C.

oxygen

D.

nitrate

Correct answer is A

Proper light in the aquarium serves as a form of energy for the photosynthetic plants and animals, hence it is very important.