Which of the following is a living fossil?

$S$ Statement: Aquatic life,gills,fins,and scales are characteristics of the fish group.
$R$ Reason: External ear (pinna) and hair on the body are characteristics of the mammalian group.
$(a)$ Both $S$ and $R$ are true,$R$ is the correct explanation of $S$.
$(b)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(c)$ $S$ is true and $R$ is false.
$(d)$ $S$ is false and $R$ is true.
$(e)$ Both $S$ and $R$ are false.

Radial symmetry occurs in

Which pair of animals are not included in mammals?

The term "phylum" in animal classification was coined by

Which of the following is an incorrect pair regarding the classification of organisms?