Question 1
Give three examples of continuous variations in human beings
Answer
- Height
- Weight
- Skin colour
- Weight
- Skin colour
Question 2.
(i) Name the main product of the dark stage of photosynthesis
(ii) State the importance of chlorophyll in photosynthesis
Answer
(i) Glucose
(ii) Chlorophyll traps light for photolysis
(ii) Chlorophyll traps light for photolysis
Question 3
(a) Define the term balanced diet
(b) State the importance of roughage in a diet
Answer
(a) Balanced diet - It is a diet that consists of all classes of food/ carbohydrates , protein , lipids , water, mineral salts, and vitamins; taken in their right proportions for a healthy body
(b) Roughage add bulk to the food hence facilitating peristalsis
(b) Roughage add bulk to the food hence facilitating peristalsis
Question 4
(a) How is the fovea centralis adapted for its function in human eye
(b) A person was not able to see far objects clearly but could view near objects clearly. Name the eye-defect the person had
(c) How can the defect be corrected
Answer
(a) It has a high concentration of cones for high visual acuity
(b) Short – sightedness/ myopia
(c) Wearing concave lenses
(b) Short – sightedness/ myopia
(c) Wearing concave lenses
Question 5
(a) What is fertilization ?
(b) Explain how double fertilization takes place in plants
Answer
(a) Fertilization – fusion of male and female nuclei gametes; to form a zygote
(b) One male nuclei fuses with egg to form a (diploid) zygote; while the other male nuclei fuses with (two) polar cells to form (triploid) endosperm nucleus
(b) One male nuclei fuses with egg to form a (diploid) zygote; while the other male nuclei fuses with (two) polar cells to form (triploid) endosperm nucleus