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.

Fact: the force of water against the seed coat causes a root to emerge from a seed.
a root to emerge from a seed.

Fact: plant reproduction often requires pollen.
bees carry pollen.

Fact: chemical weathering causes iron in rock to oxidize.

chemical weathering.