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.

[Q]: Fact: Lung cancer is most often caused by exposure to tobacco smoke.
[A]: lung cancer also called.


[Q]: Fact: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past.
[A]: fish water animal.


[Q]: Fact: Invertebrates are animals that lack a vertebral column, or backbone.
[A]:
Invertebrate.