WAEC Biology Past Questions & Answers

1.

The eye defect caused by an uneven curvature of the cornea or lens or both is

A.

myopia

B.

presbyopia

C.

astigmatism

D.

hypermetropia

Correct answer is C

Astigmatism is a common refractive error of the eye that occurs when the cornea or lens has an irregular shape. In a normal eye, the cornea and lens have a smooth, evenly curved surface, similar to a sphere. However, in astigmatism, the cornea or lens may be more curved in one direction than the other, resulting in a refractive error.

2.

Stunted growth and small yellow leaves in plants are symptoms of the deficiencies of

A.

nitrogen

B.

iron

C.

sulphur

D.

magnesium

Correct answer is B

Iron deficiency in plants leads to chlorosis, which is the yellowing of leaves. Chlorosis occurs because iron is necessary for the formation of chlorophyll, which is the green pigment in plants that absorbs light energy for use in photosynthesis. Without sufficient iron, the plant cannot produce enough chlorophyll, leading to yellow leaves. Stunted growth is also a symptom of iron deficiency as iron is essential for various metabolic processes including DNA synthesis.

3.

An example of a process that involves osmosis is the

A.

movement of water from root hairs into cortical cell

B.

reabsorption of food nutrients from the kidney into blood capillaries

C.

translocation of starch from leaves to all parts of a plant

D.

movement of digested food from ileum into blood capillaries

Correct answer is A

Movement of water from root hairs into cortical cells involves osmosis. When a plant's roots absorb water from the soil, it passes through the root hairs and moves into the cortical cells (which are part of the root's inner layer) through osmosis. This osmotic movement of water helps maintain water balance and nutrient distribution within the plant.

4.

Which of the following characteristics shows discontinuous variation in plants?

A.

flower colour

B.

Leaf size

C.

plant height

D.

fruit size

Correct answer is A

Colour of flower: The colour of flowers in plants typically shows discontinuous variation. Flowers can have specific colors like red, blue, yellow, or white, and individuals within a population will usually exhibit one of these distinct flower colors. There are no intermediate or blending colors between the different categories.

5.

Placentation in fruits is referred to as the

A.

arrangement of ovules in the ovary of a flower

B.

part of the ovary where the ovules originate and remain till maturity

C.

ovules borne on a central column of tissues in an ovary

D.

formation of a single carpel joined at the two edges of an ovule

Correct answer is A

Placentation in fruits refers to the arrangement of ovules within the ovary of a flower, and it is directly related to seed development and fruit formation.