Cleidoic egg is an adaptation for

Assertion $A$: Organisms show variations to adapt and utilize the environment to the maximum extent.
Reason $R$: Variations lead to the formation of new species.
Which option is correct for Assertion $A$ and Reason $R$?

Which one of the following is not a living fossil?

Match the following columns:

Column-$I$	Column-$II$
$(a)$ Darwin	$(i)$ Finches
$(b)$ Hugo de Vries	$(ii)$ Dead yeast
$(c)$ Pasteur	$(iii)$ Evening primrose

Identify the dinosaur shown in the figure.

Normally,gametes are disease-free in human beings or even in other animals because: