Here's why:
* Traits are determined by genes: Genes come in pairs, with one copy inherited from each parent.
* Dominant and Recessive alleles: Each gene has different versions called alleles. Some alleles are dominant, meaning they'll always be expressed if present. Others are recessive, only expressed if two copies of the recessive allele are present.
* Hidden traits: If an individual has one dominant and one recessive allele for a trait, the dominant allele will be expressed, and the recessive allele will be hidden.
Example:
* Brown eyes (B) are dominant over blue eyes (b).
* A person with the genotype Bb (one brown eye allele and one blue eye allele) will have brown eyes. The blue eye allele is recessive and hidden.
* A person with the genotype bb (two blue eye alleles) will have blue eyes, as there are no dominant brown eye alleles present to mask the recessive blue eye alleles.
