What is the answer im not sure

If assuming tasting ptc as a simple gene trait,what other genotype would you select to put in this missing genotype box that could result in this phenotype

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

Lupe is a carrier for color blindness. her husband clifford is colorblind. if lupe and clifford have four children, what's the probability of a boy being colorblind?