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.

[Q]: ignace murwanashyaka (14 may 1963 16 april 2019) was a rwandan rebel leader.
[A]: ignace murwanashyaka

[Q]: zirconium is a chemical elemental metal.
[A]: zirconium

[Q]: mucus (mucous), or slime, is a slippery liquid.
[A]:
mucus