Given a fact, create a question that can be answered using the fact. Construct the question such that it is unambiguous, has a unique answer and the answer can be given using the fact.

Fact: recycling has a positive impact on the environment
To be a friend of the environment?

Fact: a cactus stem is used for storing water
Someone stranded in the Sahara can potentially save their life with a?

Fact: rain is a source of water

Rain helps?