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

Antibodies recognize and combine with harmful materials, including both toxic chemicals and invasive microorganisms.
Which proteins recognize and combine with harmful materials, including both toxic chemicals and invasive microorganisms?

Carried through body happens if cancer cells enter the blood stream.
What happens if cancer cells enter the blood stream?

Oxygen element chemically weathers rock by combining with a metal.
What element chemically weathers rock by combining with a metal?