GCE O Level Biology: past questions and revision

Newly transplanted seedings wilt on a windy sunny day. This is:

1. To reduce excessive water loss.
2. Because they lose water faster than they are absorbing.
3. Because the guard cells become very turgid.
4. Because the seedlings do not yet have a thick cuticle to resist transpiration.

First statement: The anopheles mosquito transmits Plasmodium. / Second statement: Anopheles mosquito feeds on the blood of its host causing malaria.

1. If both statements are true and the second statement is a correct explanation of the first.
2. If both statements are true and the second statement is NOT a correct explanation of the first.
3. If the first statement is true and the second statement is false.
4. If the first statement is false and the second statement is true.

In a human being, in the face of danger: 1 Much ADH is secreted. 2 Heart beats faster. 3 Pupil opens wider.

1. If 1, 2 and 3 are all correct
2. If 1 and 2 only are correct
3. If 2 and 3 only are correct
4. If 1 only is correct

First statement: A normal couple may give birth to a sickle-cell child. / Second statement: Sickle cell is caused by a dominant gene.

1. If both statements are true and the second statement is a correct explanation of the first statement.
2. If both statements are true and the second statement is NOT a correct explanation of the first statement
3. If the first statement is true but the second Statement is false.
4. If the first statement is false but the second Statement is true.

In a farm land, it is noticed that maize plants found amongst leguminous plants, were seen to grow more vigorously than in areas where the leguminous plants were absent. How can this be explained?

1. The leguminous plants make more water available to the maize plants.
2. The leguminous plants provide shade to the maize plants.
3. The leguminous plants increase the nitrogen content of the soil.
4. The leguminous plants conserve more soil water.