$Pteris$ and $Adiantum$ resemble each other in having:

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?

$A$ plant having vascular supply,producing spores but lacking seeds is a

The heart-shaped prothallus of a fern bears:

$A$: Seeds are formed by some species of spike moss.
$R$: All conditions for seed habit are fulfilled by these species of spike moss.

To which of the following groups would you assign a plant that has a vascular supply,lacks ovules,and reproduces by means of spores?