What are the keywords in the following sentence? robot is meant to be a part of the family .
family, part, robot

What are the keywords in the following sentence? An airport filled with jets parked on top of it's tarmacs.
airport, jet, park, tarmac

What are the keywords in the following sentence? an ancient defensive bridge giving access to town
bridge, give, town

What are the keywords in the following sentence? metabolism all chemical reactions occurring within an organism
metabolism, occur, organism, reaction