Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

[EX Q]: child development refers to biological, psychological and emotional changes that happen in humans between birth and the end of adolescence, at which time the individual goes from dependence to independence.
[EX A]: child development

[EX Q]: san diego creek is a small northwest-flowing river in orange county, california.
[EX A]: san diego creek

[EX Q]: murmansk (russian: Му́рманск) is a port city in northwestern russia.
[EX A]:
murmansk