What is the nature of the gametophytic stage in Pteridophytes?

Cambium is absent in ..........

The place where the sporangium of a fern bursts open is called:

Which of the following pteridophytes belongs to the class $Pteropsida$?

$A$: Events precursor to the seed habit are seen in some members of pteridophytes.
$R$: Development of the zygotes into young embryos takes place within the female gametophyte.

The antherozoids of Dryopteris are .......