The Biogenetic Law was proposed by:

In the evolutionary history of the human heart,it is observed that it passed through a two-chambered heart like that of fish,to a three-chambered heart like that of amphibians,and finally became a four-chambered heart. Which concept is closest to this statement?

Fossil $X$ is older than fossil $Y$. The most evident answer is:

Fossilization occurs where

In humans,the nictitating membrane is a/an....

Archaeopteryx is a connecting link between which of the following?