Question

1. two parents with brown eyes have given birth to a baby with blue eyes. explain the aspect of human genetics that make this possible.

Explanation:

Eye - color is determined by genes. Brown eye - color is a dominant trait (represented by a dominant allele, say B), and blue eye - color is a recessive trait (represented by a recessive allele, say b). The parents, having brown eyes, could be heterozygous (Bb). When they have children, there is a 25% chance of two recessive alleles (bb) coming together, resulting in a blue - eyed baby.

Answer:

The parents are likely heterozygous for eye - color. They each carry one dominant allele for brown eyes and one recessive allele for blue eyes. Through the process of genetic inheritance and the combination of alleles during fertilization, their offspring received two recessive alleles for blue eyes.