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

Input: Consider Input: Passage: With the naked eye, bacteria just look like a slimy smear on a petri dish. How can we study them in more detail? The invention of the microscope has allowed us to see bacteria, cells, and other things too small to be seen with the naked eye. Answer: slimy smear

Output: How does the bacteria look when seen with the naked eye?

Input: Consider Input: Passage: A front forms at the boundary between two air masses. Types of fronts include cold, warm, occluded, and stationary fronts. Clouds, precipitation, and storms commonly occur along fronts. Answer: a front

Output: What forms at the boundary between two air masses?

Input: Consider Input: Passage: Shortly after eating, there is a surplus of glucose in the body. Some of it will be used immediately, but the rest is stored in the form of glycogen. Between meals, when the level of glucose in the blood drops below a certain point, a signal is sent to the liver that says "make more glucose. " In response, the glycogen in the liver is broken down and the resulting glucose is released into the bloodstream. Answer: liver
Output: Between meals, when the level of blood glucose drops below a certain point, a signal is sent to what organ saying "make more glucose"?