Use the following pedigree (Figure 14.3) for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. Figure 14.3 -What is the genotype of the deceased individual in generation II?
A) homozygous for a gene for colon cancer B) homozygous for both cancer alleles from his mother C) heterozygous for a gene for colon cancer D) affected by the same colon cancer environmental factor as his mother E) carrier of all of the several known genes for colon cancer