Plasma membranes are selectively permeable. this means that

a)anything can pass into or out of a cell as long as the membrane is intact and the cell is healthy.
b)plasma membranes must be very thick.
c)the plasma membrane allows some substances to enter or leave a cell more easily than others.
d)glucose cannot enter the cell.

Choose the best definition of allele. a. one of several possible versions of a gene, which each produce a different phenotype b. an organism that's purebred for a given trait c. the process of fertilizing a plant with pollen from another plant d. a set of genes that are located on the same chromosome and so are tightly linked