The large intestine absorbs water, fats, and salts.

A. Sperm; semen: Sperm is the male gamete, and semen is the fluid that contains sperm, but these are not analogous to the ovary, which is a gonad.

B. Testis; semen: The testis is the male gonad that produces sperm, but semen is the fluid that contains sperm. The analogous structure to the ovary is the testis, but this pairing with semen is not correct.

C. Semen; sperm: Semen is the fluid containing sperm, while sperm is the male gamete. Neither is a gonad, so this pairing is not analogous to the ovary.

D. Testis; sperm: The testis is the male gonad that produces sperm, making it analogous to the ovary, which is the female gonad that produces eggs.

A. Chief cells; hydrochloric acid (HCl); parietal cells: Pepsinogen is produced by chief cells, and it is activated into pepsin by hydrochloric acid (HCl) secreted by parietal cells.

B. Chief cells; carbonic anhydrase (CAH); parietal cells: Chief cells produce pepsinogen, but it is not activated by carbonic anhydrase. Instead, it is activated by HCl.

C. Parietal cells; carbonic anhydrase (CAH); chief cells: Pepsinogen is produced by chief cells, not parietal cells, and its activation involves HCl, not carbonic anhydrase.

D. Parietal cells; hydrochloric acid (HCl); chief cells: Pepsinogen is produced by chief cells, not parietal cells, and is activated by HCl.