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

Example Input: Line graphs are especially useful for showing changes over time.
Example Output: Line graphs are especially useful for showing changes over what?

Example Input: Producing sperm and secreting testosterone are the main functions of male reproductive system system.
Example Output: Producing sperm and secreting testosterone are the main functions of what system?

Example Input: Iron in the soil causes mars to look red.
Example Output:
What is in the soil that causes mars to look red?