In $Selaginella$,megaspores are about how many times larger than microspores?

In $Pteridophytes$ / $Dryopteris$,meiosis occurs at the time of:

Heteromorphic alternation of generations is found in

Adaxial outgrowth from the base of leaves in $Selaginella$ is called:

The site of spore formation in $Dryopteris$ is

How many of the following statements are true about $Azolla$?
$(a)$ It is free-floating.
$(b)$ It has bilobed leaves.
$(c)$ It is nitrogen-fixing.
$(d)$ It is a climber.
$(e)$ It has Aerenchyma in the ventral lobe of the leaf.