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

Sexually do invertebrates reproduce.
How do invertebrates reproduce?

Reptiles are described by the term ectothermic, which means their internal temperature depends on the temperature of their environment.
Reptiles are described by what term that means their internal temperature depends on the temperature of their environment?

Wells that produce petroleum does most natural gas come from.

Where does most natural gas come from?