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

Example Input: Some meteorites are made of iron and nickel and are thought to be very similar to the core of the earth.
Example Output: Some meteorites are made of iron and nickel and are thought to be very similar to what part of the earth?

Example Input: Electron transport is the final stage of aerobic respiration, when energy from the krebs cycle is transferred to atp.
Example Output: What is the final stage of aerobic respiration, when energy from the krebs cycle is transferred to atp?

Example Input: You call a substance that cannot be separated into smaller pieces, which is also defined by the number of protons it has, a(n) element.
Example Output:
What do you call a substance that cannot be separated into smaller pieces, which is also defined by the number of protons it has?