Why is it more efficient to perform a test cross with a homozygous recessive donor than a homozygous dominant donor? how could the same information still be found with a homozygous dominant donor?

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.

cell division is not regulated in tumor cells.