Question

In humans, brown eyes (B) are dominant to blue eyes (b). Diagram the following cross by drawing a Punnett SquareHomozygous blue x homozygous blue

Answer 1

As blue eyes is a recessive trait, the homozygous blue alleles are bb.

To fill the Punnett Square we must place the alleles from one of the parents (bb) horizontally oriented on the top of a 3x3 diagram, and the alleles from the other parent (bb) vertically oriented on the left border of the diagram. After that, we must cross each one of the alleles from one parent with the alleles of the other, positioning the result of those crossings (bb) in the blank space where those alleles meet, as follows:

Therefore, all of the offspring will be recessive homozygous (bb).