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

Input: Consider Input: People stopped adding lead to gasoline because of environmental pollution.

Output: Why did people stop adding lead to gasoline?


Input: Consider Input: Diffusion process helps absorptive protists absorb food molecules across their cell membranes.

Output: Which process helps absorptive protists absorb food molecules across their cell membranes?


Input: Consider Input: Sphygmomanometer is used to measure blood pressure.


Output: What is used to measure blood pressure?