What is true of maple trees and saguaro cactuses? a. They are the same size.
b. They grow in different climates.
c. They have different root systems.
d. They need the same amount of water.

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

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Which of the following statements about archaea and bacteria is true? a. neither is single-celled. b. they both have nuclear membranes. c. neither reproduces by binary fission. d. they both lack a nuclear membrane.