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: molar mass is the mass of a substance that has 6.022 × 10 atoms (avogadro's number).

A: molar mass
****
Q: the centre for conflict and peace studies (abbreviated caps) is an independent research organization, which started in july 2006.

A: centre for conflict and peace studies
****
Q: a transport hub (also transport interchange) is a place where passengers and cargo are exchanged between transport modes.

A:
transport hub
****