Question

A man and his wife are both heterozygous for brown eyes (B). They have six children all of whom have blue eyes. How can this happen?

Answer 1

B = brown eyes allele
b = blue eyes allele

Mom and Dad are both heterozygous, so they're both Bb.

Answer 2

d

Answer 3

The Draw button doesn't work! I wanted to draw you a Punnet square!

Basically, Mom and Dad both have a little b allele to give. Mom's little b allele ends up with Dad's little b allele in the offspring - so the offspring is bb. Blue eyes.

Not very likely six times in a row, but there's your explanation.

Answer 4

either chance, or they haven't finished having kids yet