Why is $Adiantum$ known as the 'walking fern'?

In most of the pteridophytes,all the spores are of similar kind. Such plants are called ......

The rhizophore of $Selaginella$ is

Assertion $(A)$: In $Equisetum$,sexual reproduction occurs through sex organs like antheridia and archegonia.
Reason $(R)$: In pteridophytes,the gametophytic phase is long-lived and responsible for sexual reproduction.

The sorus of $Dryopteris$ fern is:

Sporangia are associated with sporophylls. In $P$ plants,sporophylls are distinct,while in $Q$ plants,sporophylls form compact structures called strobili or cones.
$P \quad Q$