Define the term fossil and give its significance in evolution.

Fossils are the petrified remains and or impressions of hard parts of extinct organisms preserved in the sedimentary rocks or some other medium.
Significance of fossils :
(a) These form most direct and reliable evidence of evolution as these represent actual remains of the extinct organisms.
(b) Fossils study has helped to trace, complete phylogeny of animals like horse, elephant, man etc.