A. crossed-over B. Mendelian C. heterozygous D. homozygous 2. Traits that are influenced by many genes at different loci and are considered to be A. Nucleic B. Pleiotropic C. Polygenic D. Somatic 3. Mendel's principle or law of segregation suggests that: A. only one of the two genes copies present in an organism is distributed to each gamete B. genes on a chromosome are always passed down together C. gametes contain both gene copies from a parent .