Heterozygous tall plants were crossed with pure-breeding dwarf plants of the same species. What were the approximate percentages of the offspring?

In genetics, the outcome of a cross between two individuals can be predicted using Punnett squares. When a heterozygous tall plant (Tt) is crossed with a pure-breeding dwarf plant (tt), the resulting offspring will inherit one allele from each parent.

The Punnett square for this cross would be:

  T   t
t Tt  tt
t Tt  tt

As we can see from the Punnett square, there are two possible genotypes for the offspring: Tt (tall) and tt (dwarf). The ratio of the offspring with the two different genotypes is 1:1 or 50%:50%.

Therefore, the approximate percentages of the offspring are 50% tall and 50% dwarf. This means that half of the offspring will have the same phenotype (physical appearance) as the heterozygous parent (tall) and the other half will have the same phenotype as the pure-breeding parent (dwarf).