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: an animal requires energy to move.
animal energy from.

Fact: stalactites are formed by deposition.
deposition sand limestone.

Fact: Osteoporosis is a disease in which osteoclasts are more active than osteoblasts.

dowager's hump.