A scientist crosses a homozygous red flower with a homozygous white flower. All of the resulting off spring are heterozygous with red flowers. Explain how this is possible.

the red flower gene is dominant, white is recessive, the cross was RR x rr yielding 4 Rr crosses with red flowers.

It must be because the red flowers are dominant to the white flowers. This just means that the red flowers are expressed more (let's give it the allele A) the red flower would have an A allele and the white flower would have the a allele (lowercase). All of the alleles in the offspring look like Aa Bc they are heterozygous and the A overpowers a so that results in all red flowers