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

Which of the following is a characteristic feature of ferns?

What is the number of chromosomes in each cell of the root of Ophioglossum?

In some of the pteridophytes and gymnosperms,the sporophylls aggregate at the apices of the main stem or its branches to form definite compact structures. These compact structures are called:

Which of the following stages is dominant in Pteridophytes?

From an evolutionary point of view,the retention of the female gametophyte with the developing young embryo on the parent sporophyte for some time is first observed in: