Select the correct option for the following classification: Vertebrate and Invertebrate.

$A$ blastula which is solid,is known as

Which of the following is a correct matching set?

All worms are

$S$ 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.

All worms are ........