Capillary walls serve as effective permeability barriers for
a. oxygen and carbon dioxide.
b. electrolytes.
c. glucose
d. proteins.
e small water-soluble molecules.

In a population that is in hardy-weinberg equilibrium, there are two possible alleles for a certain gene, a and a. if the frequency of allele a is 0.4, what fraction of the population is heterozygous? a. 0.40 b. 0.60 c. 0.16 d. 0.48