Fossil $X$ is older than fossil $Y$ if
$X$ was found deeper in sediment than $Y$
$Y$ was found deeper in sediment than $X$
$Y$ had less vestigial organs
Fossil $Y$ had a homologous and analogous organs of $X$
Replica plating experiment was performed to prove the
Evolution of different species in a given area starting from a point and spreading to other geographical areas is known as
Main basis of Neo-Darwinism is