Answer:
100% of the offspring are blue butterflies.
Explanation:
B is a dominant allele, determining the blue color of a butterfly.
b is a recessive allele. This means a bird with bb genotype is yellow in color.
A pure blue butterfly (BB) produces only B gametes, and a pure yellow butterfly (bb) gives onl b gametes.
Therefore, the offspring in the BB x bb cross are all blue in color.
