'Male shield fern' is:

The evolutionary advanced features of $Selaginella$ are:
$(a)$ Heterospory
$(b)$ Endosporic development of gametophyte
$(c)$ Reduced gametophyte
$(d)$ Localization of sporangium-bearing appendages in strobili
$(e)$ Unisexual gametophytes
$(f)$ Fertilization with the help of water

The positively geotropic structure,the rhizophore of $Selaginella$,is:

Which of the following is a heterosporous pteridophyte?

Which of the following are seedless plants that possess vascular tissues?

The seed habit was first established in .........