The secondary wood of $Pinus$ is characterised by:

Consider the following statements regarding gymnosperms and choose the correct option.
$I.$ In gymnosperms,the male and female gametophytes have an independent existence.
$II.$ The multicellular female gametophyte is retained within the megasporangium.
$III.$ The gymnosperms are heterosporous.
Of these statements:

Transfusion tissue is found in

Assertion $(A)$: Gymnosperms lack true fruits.
Reason $(R)$: Gymnosperms lack an ovary.
Which option is correct for Assertion $(A)$ and Reason $(R)$?

In which one of the following do male and female gametophytes not have a free-living independent existence?

In $Gymnosperms$, the endosperm is .......