LIFE SCIENCE

Detailed explanation-1: -Brown eye colour is dominant over blue eye colour. Therefore, for the brown-eyed parents having blue-eyed child, the possibility is that both have heterozygous genotype i.e. Bb. Therefore, from the square below, it is clear that there is a 25% possibility of blue-eyed (bb) child.

Detailed explanation-2: -The Punnet square below shows the probabilities for eye color in the offspring of two heterozygous (Bb) parents. If both parents are heterozygous for eye color, the probability that a child will have blue eyes is 14 or 0.25, for each child, because each birth is an independent event.

Detailed explanation-3: -Someone with brown eyes may be carrying one blue allele and one brown allele, so a brown-eyed mother and a blue-eyed father could give birth to a blue-eyed child. Now mix in a third green allele, which is dominant to blue, but recessive to brown.

Detailed explanation-4: -In humans, right handedness (R) is dominant over left handedness (r), and brown eyes (B) are dominant over blue eyes (b). These genes are on different chromosomes.