Consider the following statements regarding gymnosperms and choose the correct option.
I. In gymnosperms, the male and female gametophytes have an independent existence.
II. In gymnosperms, the multicellular female gametophyte is retained within the megasporangium.
III. The gymnosperms are heterosporous.
Unlike bryophytes and pteridophytes, in gymnosperms male and female gametophytes do not have an independent free-living existence. In gymnosperms, multicellular female gametophyte is retained within the megasporangium. Gymnosperms are heterosporous.