In $Lycopodium$,the antherozoids are .......

Heterospory,i.e.,the formation of two types of spores—microspores and megaspores—is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in the plant kingdom?

Identify the plant shown in the given figure.

Classify pteridophytes into their four main groups and provide an example for each.

In some pteridophytes, sporophylls form distinct compact structures called $A$ in $B$ and $C$. Here $A, B$, and $C$ refer to:

$A$: 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.