WAEC Biology Past Questions & Answers - Page 83

411.

An example of homeostasis in living organisms is

A.

cooling effect resulting from evaporation of water from the body surface

B.

root hairs of a plant growing towards the source of light

C.

changing of the body colour of chameleon to match the colour of the foliage on which it is resting

D.

the release of phosphorus into the phloem of a plant growing in a phosphorus-deficient soil

Correct answer is D

Homeostasis is a living organism's way of maintaining a stable internal environment even in the event of external environmental changes. When the plant keeps supplying phosphorus to the phloem even in the case of a deficiency in the soil, it maintains a steady balance on its inside irrespective of the lack in the soil.

412.

Which of the following is NOT an excretory product of animals?

A.

carbondioxide

B.

urea

C.

sweat

D.

oxygen

Correct answer is D

Animals take in oxygen in respiratory process, taking out carbondioxide. 

413.

Which of the following structures would carry out cellular respiration? A

A.

germinating seed

B.

decolorised leaf

C.

dry leaf

D.

boiled cowpea

Correct answer is A

Germinating seeds respire by using oxygen and producing carbon dioxide gas, they respire in the similar way as animals.

414.

A seedling was made to stand in a solution of red ink for three hours and a transverse section of the stem was examined under the microscope. The process being investigated was

A.

the importance of microelements to plants

B.

ascent of water through the xylem

C.

diffusion of colored substances

D.

distribution of food in plants

Correct answer is C

No explanation has been provided for this answer.

415.

The odontoid process is found on the

A.

axis vetebra

B.

atlas vetebra

C.

thoracic vetebra

D.

sacral vetebra

Correct answer is A

The odontoid process is a projection of the axis vetebra. It is seen at its point of joining with the body.