In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short? A) 1 B) 1/2 C) 1/4 D) 1/6 E) 0
The answer is E) 0. If: A - dominant allele, a - recessive allele, then: AA - dominant homozygous (tall), aa - recessive homozygous (short), Aa - heterozygous (tall). A heterozygous plant (Aa) is crossed with a homozygous tall plant (AA): Parental generation: Aa x AA F1 generation: AA AA Aa Aa All of the offspring is tall (AA or Aa), since tall is dominant to short. There is no chance for offspring to be short (aa).