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

All of the populations that live in the same area make up a(n) community, which includes populations of different organisms.
All of the populations that live in the same area make up what type of group, which includes populations of different organisms?

The metallic bond is responsible for the properties of metals.
What is responsible for the properties of metals?

Algae is a promising alternative to traditional crops for biofuel type of fuels.
Algae is a promising alternative to traditional crops for what type of fuels?