D : the number of generations in one population
Answer:
C. A concentration gradient must exist.
Adenine pairs with thymine. They form complementary pairs withone another during replication of the parent strand, forming the complement strand. If thymine is present for 30% of the bases, then its complement, adenine, will also be present in 30% of the bases.
I believe the corre term to fill in the blank is "a protein gradient." Chemiosmosis uses a protein gradient to supply the energy necessary to phosphorylate adp to atp. It<span> is the diffusion of hydrogen ions (protons) across the biological membrane via the ATP synthase.</span>
That would be the concentration gradient of hydrogen ions(protons). See the attached pic:)