WAEC Biology 2023 Papers

Concept:The sex of a baby is determined by the sperm that fertilises the mother's egg.Explanation:A mother always passes on an X chromosome.A father passes on either an X chromosome or a Y chromosome.If the father passes on an X, the child is female ($XX$).If the father passes on a Y, the child is male ($XY$).These two possibilities are equally likely.So, there is 1 favourable outcome (male) out of 2 possible outcomes.Thus, the probability of a male child is $\frac{1}{2}$.Answer:B. $\frac{1}{2}$