Answer:
The correct answer is option True.
Step-by-step explanation:
Ferns are the seedless tracheophytes belonging to group pteridophytes of the plant kingdom. The life cycle of a fern is divided into two phases: the haploid gametophytic stage and diploid sporophytic stage.
The gametophyte is formed from the sporophytic spores after they are germinated on a suitable substratum. Sporophyte after germination forms a bisexual heart-shaped structure with no vascular tissues so uses rhizoids for attachment. This formed gametophyte is known as "prothallus".
Thus, the gametophyte structure is known as prothallus is true.