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

Input: Consider Input: Passage: Mixtures have different properties depending on the size of their particles. Three types of mixtures based on particle size are solutions, suspensions, and colloids, all of which are described in Table below . You can watch videos about the three types of mixtures at these URLs:. Answer: solutions, suspensions, colloids

Output: What are the three types of mixtures?

Input: Consider Input: Passage: You've probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point . If this temperature is below freezing, ice crystals of frost form instead of dew ( Figure below ). The dew point occurs at 100 percent relative humidity. Can you explain why?. Answer: dew point

Output: What is the name of the "point" that refers to the temperature at which water vapor condenses?

Input: Consider Input: Passage: Population density is the average number of individuals in a population per unit of area or volume. For example, a population of 100 insects that live in an area of 100 square meters has a density of 1 insect per square meter. If the same population lives in an area of only 1 square meter, what is its density? Which population is more crowded? How might crowding affect the health of a population?. Answer: population density
Output: What is the term for the average number of individuals in a population per unit of area or volume?