T.H.Morgan and his colleagues found that among the offspring of genetic crosses,parental phenotypic classes were the most frequent,while recombinant classes occurred less frequently.This observation led Morgan to conclude that
A)all genes are linked. B)alleles of linked genes assort independently. C)alleles of some genes assort together. D)genes on different chromosomes assort independently. E)genes on different chromosomes do not assort independently.