4. A chemical or physical agent in the environment that causes a mutation is called a
A. leucism.
B. point mutation.
C. mutagen
D. polyploidy

Compare and contrast region e in the illustration above with region d. describe the physical characteristics of each region.

Which layer will become saturated first when rain falls?

Many farmers prefer cattle without horns because it is safer for their herds. the allele for no horns (n) is dominant to the allele for the presence of horns (n). a farmer mates a male with horns to a heterozygous female without horns. what is the chance that the offspring will have horns?