WAEC Biology 2009 Objective — Question 56

Question 56 of 60 from the West African Examinations Council (WAEC) Biology 2009 Objective paper, with the correct answer and a full explanation.

The percentage probability a normal male married to a carrier woman would have a haemophilic male child is

A. A. 35%
B. B. 50%Correct
C. C. 75%
D. D. 100%

Explanation

The man is XY (normal) and the woman is XhX (carrier). Since males can never be carriers of a sex-linked disease - they are either fully affected or fully free - the cross produces two male children, of whom one will be haemophilic (XhY) and one will be normal (XY), giving a 50% probability.

Sign up free to unlock

Score tracking
Practice history
Saved questions
Progress dashboard
Personalized sessions
Weak-topic breakdown

…and/or go further with premium services and No Ads.

Create free account

More questions from Biology 2009 Objective More Biology past papers