(a) Explain briefly how the human ear carries out its function of balancing.
(b)
(i) Make a drawing, 8 cm - 10 cm long, of the structure of the human ear and label it fully.
(ii) Describe briefly the structure of the middle ear in humans.
(a)
(i) What is a deficiency disease?
(ii) Complete the table below by naming five nutrient deficiency diseases in humans and stating one remedy for each of the diseases.
| Nutrient Deficiency Disease | Remedy |
|---|---|
(b) Outline a chemical test for:
(i) Starch in a tuber of yam.
(ii) Glucose in orange fruit.
(a) Complete the table below:
| Disease | Causative Organism | Vector | Control |
|---|---|---|---|
| Cholera | |||
| Trypanosome | |||
| Female Anopheles mosquito | |||
| Ringworm | None |
(b) Explain briefly the biological basis of preserving foods using each of the following methods:
(i) Salting
(ii) Irradiation
(iii) Smoking
(a) Explain briefly:
(i) Independent assortment of genes.
(ii) The reason blood group O in humans can only exist in homozygous form while blood groups A and B can exist in both homozygous and heterozygous forms.
(b) Complete the table below by naming the classes of vertebrates in their evolutionary trend and giving one example of each class:
| Classes of Vertebrates | One Example |
|---|---|
(a) Explain briefly the following types of fertilization in animals:
(i) External fertilization.
(ii) Internal fertilization.
(b) Name two groups of animals for each type of fertilization mentioned in (a).
(c)
(i) If the placenta in a pregnant woman is detached from the uterine wall, give three effects this will have on the foetus.
(ii) Name three other features in the uterus of a pregnant woman that are useful for the development of the foetus.
(d) Explain briefly how the activities of organisms bring about dynamic equilibrium in the habitat.
(e) State four problems that organisms in the intertidal zone of a marine habitat could encounter.
(f) Explain briefly the reasons the following factors are necessary for germination:
(i) Moisture.
(ii) Viable seeds.
(g) Explain briefly why light energy is considered a limiting factor in the production of food by autotrophs.