What causes the differences in traits between
organisms of the same species?

Different organisms vary in how they look and function because they have different inherited information; the environment also affects the traits that an organism develops. In sexual reproduction, each parent contributes half of the genes acquired by the offspring resulting in variation between parent and offspring.

Explanation:

Twittr is pichu_the_liberal

the offspring would all be white. if the parents are both white flowers then they have the genotype rr, which when crossed results in an all white punnet square.