In $Pteridophytes$, the main plant body is $........$.

In which of the following plants is the gametophytic stage considered secondary or reduced?

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.

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

If a sporangium is derived from a single cell,it is called:

Evolutionarily, the first terrestrial plants to possess vascular tissues are