Given a scientific passage and an answer, generate a question for the given answer.

[EX Q]: Passage: Opposite charges attract, and like charges repel. Answer: attract
[EX A]: What do opposite charges do to one another?

[EX Q]: Passage: Glutathione is a low-molecular-weight compound found in living cells that is produced naturally by the liver. Healthcare providers give glutathione intravenously to prevent side effects of chemotherapy and to prevent kidney problems. Answer: liver
[EX A]: Glutathione is a low-molecular-weight compound found in living cells that is produced naturally by what?

[EX Q]: Passage: Buoyant force is an upward force that fluids exert on any object that is placed in them. The ability of fluids to exert this force is called buoyancy . What explains buoyant force? A fluid exerts pressure in all directions, but the pressure is greater at greater depth. Therefore, the fluid below an object, where the fluid is deeper, exerts greater pressure on the object than the fluid above it. You can see in the Figure below how this works. Buoyant force explains why the girl pictured above can float in water. Answer: buoyant force
[EX A]:
What is an upward force that fluids exert on any object that is placed in them?