There are four children in the Smith family. One child has blue eyes and blonde hair. The other three children have brown eyes and blonde hair. How can you explain the difference and I color?

Eye color is an inherited trait; brown eyes are dominant over blue.

Explanation:

It is likely that one of the Smith children's parents has brown eyes while the other has blue eyes. Blue (and green) eyes are a recessive trait, while brown eyes are a dominant trait, so it is more common for Smith children to inherit the dominant trait, so three smith children have brown eyes, while only one child has blue eyes.

The boss in the color of the eyes is the genetic load! Dark-eyed parents may have light-eyed children if any ancestor has light-eyed parents, just as light-eyed parents may have dark-eyed children, this will depend on the dominance and recessiveness of inherited alleles.

It all depends on the genotype and the phenotype of the DNA.