Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Input: Consider Input: Sodium-potassium pumps help nerve cells establish a voltage across their plasma membranes.

Output: Sodium-potassium pumps help nerve cells establish a voltage across their what?

Input: Consider Input: Microscopes were first developed in the early 1600s by eyeglass makers.

Output: Microscopes were first developed in the early 1600s by this trade?

Input: Consider Input: When your brain senses that your body temperature is increasing, it sends messages to the blood vessels in the skin to increase in diameter.
Output: When your brain senses that your body temperature is increasing, it sends messages to the blood vessels in the skin to increase in what?