Answer:
The correct answer is "Aquaporin".
Step-by-step explanation:
The missing options of this question are:
A. ATP synthetase
B. Aquaporin
C. The sodium-potassium pump
D. Integrin
The correct answer is option B. "Aquaporin".
Aquaporins are microscopic channels that belong to a family of proteins that form pores. Aquaporins are also known as water channels for its specific biological role of allowing water to cross the cell membrane. The presence of aquaporins explains why water can cross cell membrane more quickly than expected, since they function as regulators of water transference.