Which of the following structures contains the vocal cords?

a. Insulin and glucagon: These hormones have opposite effects on blood glucose levels; insulin decreases blood glucose by facilitating cellular uptake, while glucagon increases blood glucose by stimulating glycogen breakdown and gluconeogenesis.

b. Ghrelin and gastrin: Ghrelin stimulates appetite, and gastrin stimulates gastric acid secretion, but they do not directly oppose each other.

c. Calcitonin and melatonin: Calcitonin lowers blood calcium levels, while melatonin regulates sleep-wake cycles; they do not act as antagonists.

d. Androsterone and estradiol: These are sex hormones with different roles but are not direct antagonists; they do not have opposing effects in the body.

a. The volume of the cell decreases: When a red blood cell is placed in a hypertonic solution (solution with a higher concentration of solutes outside the cell compared to inside), water will move out of the cell through osmosis to equalize the concentration on both sides of the cell membrane. This movement of water causes the red blood cell to shrink (crenate).

b. The permeability of the cell membrane decreases: Incorrect. The permeability of the cell membrane to water remains relatively constant.

c. The permeability of the cell membrane increases: Incorrect. Osmosis is a passive process that doesn't require increased permeability.

d. The volume of the cell increases: Incorrect. A hypertonic solution will cause the cell to lose water and shrink.