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

The sun is considered the center of the solar system.
What is considered the center of the solar system?

Salt-water biomes in the ocean are called marine biomes.
Salt-water biomes in the ocean are called what?

Fission is the radioactive process used in nuclear power plants and one type of nuclear bomb.
What is the radioactive process used in nuclear power plants and one type of nuclear bomb?