Define evolution. How does it occur? Describe how fossils provide us evidence in support of evolution.

(N/A) Evolution: The gradual unfolding of organisms from pre-existing organisms through changes since the origin of life.
It occurs because there is an inbuilt tendency to variation during reproduction due to errors in $DNA$ copying and as a result of sexual reproduction.
Fossils provide evidence for evolution by showing that although organisms in the past appeared different from existing species,they often share certain features with them. This establishes evolutionary linkages between ancestral and modern forms. Furthermore,fossils provide information about extinct species that were distinct from those existing today,helping us reconstruct the history of life on Earth.