Which is the best example of a heterozygous genotype?
A. TT
B. tt
C. TP
D. Tt

How does the study of genetic disorders such as pku biologists understand normal alleles?

Which would best keep the oxygen cycle stable? a. cutting down jungles to create farmland b. eliminating parks in large cities c. dumping toxic chemicals into the ocean d. reducing the amount of deforestation d. reducing the amount of deforestation

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -