Here's why:

* BB represents a homozygous dominant genotype. This means the organism has two copies of the dominant allele.

* Dominant alleles express their trait even when only one copy is present.

* Therefore, an organism with BB will express the dominant trait associated with that allele.

For example, if "B" represents the allele for brown eyes, an organism with BB will have brown eyes, regardless of what other alleles they might have for eye color.