21. The -ATPase plays a central role in membrane transport. Which of the following statements is correct? (1) The -ATPase is an electrogenic transporter. (2) Inhibition of the -ATPase promotes -glucose symport. (3) The -ATPase establishes ion gradients that drive secondary active transport. (A) (1) only. (B) (2) only. (C) (1) and (3). (D) (2) and (3). (E) All of the above are correct.