Question

6(a) Explain briefly the following types of fertilization in animals: (i) external fertilization; (ii) internal fertilization. (b) Name two groups of animals each that exhibit the types of fertilization in 6(a). (c) If the placenta in a pregnant woman detached from the uterine wall, give three effects this would have on the foetus.

Accepted Answer

(a)(i) In external fertilization, the female organism releases the eggs to the external environment, after which the male organism releases sperm on them.
(ii) In internal fertilization, the egg is retained in the body of the female organism and sperm is then introduced into the body of the female organism so that fertilization can take place.
(b)(i) Examples of animal groups that exhibit external fertilization are Pisces (fishes) and amphibians.
(ii) Examples of animal groups that exhibit internal fertilization are mammals, reptiles and Aves (birds).
(c) Effects if the placenta is detached from the uterine wall: It will cause the foetus to stop receiving food; it will stop the removal of waste products from the foetal blood; it may lead to still birth.

WAEC Biology 2020 Theory — Question 6

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