Question

mark is heterozygous. if b is for brown hair, and b is for blonde hair, what is mark’s genotype? bb bb bb bb

Explanation:

Heterozygous genotype means having two different alleles for a gene. Here, the alleles for hair color are B (brown) and b (blonde). So a heterozygous genotype would be a combination of the dominant (B) and recessive (b) allele, which is Bb.

Answer:

B. Bb