Biology 2020 Waec Past Questions and Answers

Question 1 :

• WAEC 2020

(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 fully.
(ii) Describe briefly the structure of the middle ear in humans.

Question 2 :

• WAEC 2020

(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.
(b) Outline a chemical test for (i) Starch in a tuber of yam (ii) Glucose in orange fruit

Nutrient deficiency disease	Remedy

Question 3 :

• WAEC 2020

(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

Question 4 :

• WAEC 2020

(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 both in homozygous and heterozygous forms.
(b) Complete the table below by naming the classes of vertebrates in their evolutionary trend and giving one example each of the classes.

Classes of vertebrate	One example

Question 5 :

• WAEC 2020

(a) Explain briefly the following types of fertilization in animals; (i) external fertilization (ii) internal fertilization
(b) Name two groups of animal each that exhibit the types of fertilization in (a)
(c)(i) If the placenta in a pregnant woman is detached from the uterine wall, give three effect 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 bout 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 that the following factors are necessary for germination; (i) moisture (ii) viable seeds
(g) Explain briefly the reason light energy is considered a limiting factor in the production of foods by autotrophs.