TASK DEFINITION: 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.
PROBLEM: fair use is the idea that it should be okay for a person to reuse something that another person has created, in certain amounts and for certain purposes, without breaking the law.

SOLUTION: fair use

PROBLEM: ammonium carbonate, also known as baker's ammonia or sal volatile, is a chemical compound.

SOLUTION: ammonium carbonate

PROBLEM: kurt julius isselbacher (september 12, 1925 – july 18, 2019) was a german-born american physician and gastroenterologist.

SOLUTION:
kurt julius isselbacher