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

Input: Consider Input: Water can be boiled to kill giardia and most other pathogens.

Output: Water can be boiled to kill giardia and most other what?


Input: Consider Input: Most protein antigens require signals from helper t cells (th2) to proceed to make antibody.

Output: Most protein antigens require signals from helper t cells (th2) to proceed to make what?


Input: Consider Input: Opaque is the term for matter that does not let any light pass through.


Output: What is the term for matter that does not let any light pass through?