What are the keywords in the following sentence? what type of organisms occupy the lowest level in every food chain or web
chain, level, occupy, organism

What are the keywords in the following sentence? portrait of a doctor in a hospital
doctor, hospital, portrait

What are the keywords in the following sentence? A worker trying to build a frame.
build, frame, worker

What are the keywords in the following sentence? an orthodox man walks past soldiers guarding the tomb of the prophet in the town
guard, soldier, tomb