Question

A variety of corn can produce yellow or white seeds. Yellow is dominant. White is recessive.

If an ear of corn contains only white corn, it must be —

A
homozygous recessive
B
heterozygous recessive
C
heterozygous dominant
D
homozygous dominant

Answer 1

A — homozygous recessive.

White is recessive, so the white phenotype appears only when the genotype has two recessive alleles (ww). Heterozygotes (Ww) would be yellow.