In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.

Palaeontologists are like detectives who (1) ________ the evidence that (2) ______ animals left behind. Those clues to what dinosaurs were like are found in fossils - the ancient (3) _______ of an organism, such as teeth, bone or shell - or (4) _______ of animal activity, such as (5) ________ and trackways.