instruction:
In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.
question:
Fact: Puberty is the period during which humans become sexually mature.
answer:
Puberty.


question:
Fact: a wheeled vehicle requires smooth surfaces.
answer:
asphalt is a smooth surface.


question:
Fact: Energy enters ecosystems in the form of sunlight or chemical compounds.
answer:

chemical compounds.