In which plant are the largest sperms found?

Resin canals are abundantly found in . . . . . . .

$A$: The scale leaves of $Araucaria$ are small and brown.
$R$: The gametophytic phase of $Araucaria$ is long-lived and subterranean.

Which is the tallest tree?

The megasporangium of $Selaginella$ is equivalent to which structure of $Pinus$?

An angiosperm is different from a gymnosperm in the absence of