If a homozygous dominant organism is crossed with a heterozygous organism, what is the likelihood of producing a heterozygous organism?

A 50%

explanation

By using a Punnett square, we can see that matching a homozygous dominant (RR) with a heterozygous (Rr) will produce four possible outcomes: RR, RR, Rr, Rr. This gives a 50% chance of Rr.