When neither gene in a genotype pair is dominant and neither gene is recessive, the genes are said to be
multiple alleles
incomplete dominant alleles
incomplete alleles

The genes are said to be incomplete dominant alleles. In incomplete dominance, there is no dominant or recessive gene. This condition results to blending of these traits. An example of this are pink roses. When dominant red roses are mated to recessive white roses, pink roses are created, which is neither red or white.

Why are plant leaves specialized structures that are generally flat and thin?   answer: to maximize the amount of light transmission through the cell layers.