Given a scientific passage and an answer, generate a question for the given answer.

Ex Input:
Passage: To harness water power, a stream must be dammed. Narrow valleys are the best for dams. While sitting in the reservoir behind the dam, the water has potential energy. Water is allowed to flow downhill into a large turbine. While flowing downhill, the water has kinetic energy. Kinetic energy makes the turbine spin. The turbine is connected to a generator, which makes electricity. Answer: kinetic energy

Ex Output:
Water is allowed to flow downhill into a large turbine to harness power. what helps the turbine spin?

Ex Input:
Passage: When there is no mass in a volume of space, the space is not curved. An object passing through such space would follow a straight line in our normal way of thinking of a straight line. Answer: curved

Ex Output:
When there is no mass in a volume of space, the space is not what?

Ex Input:
Passage: Plants that live in extremely dry environments have the opposite problem: how to get and keep water. Plants that are adapted to very dry environments are called xerophytes . Their adaptations may help them increase water intake, decrease water loss, or store water when it is available. Answer: xerophytes

Ex Output:
Plants that live in the desert are called?