Q.
Assertion : A person may be a haemophilic, only if his mother is a carrier or colourblind.
Reason : The male parent cannot pass on a sex-linked gene to his son.
Solution:
Haemophilia is a X-linked disease. As a person receives X chromosome from mother and Y from father, therefore the person may be a haemophilic if his mother is carrier of the disease. The person will be certainly haemophilic if his mother is haemophilic.

