Given a scientific question, generate a correct answer to it.

Ex Input:
What living things are considered photoautotrophs because they use sunlight and carbon from carbon dioxide to synthesize chemical energy in the form of carbohydrates?

Ex Output:
plants

Ex Input:
What control reproductive cycles, which are in turn regulated by environmental cues?

Ex Output:
hormones

Ex Input:
What do you call compounds whose properties are different because their atoms are bonded together in different arrangements?

Ex Output:
isomers