Question

Prothallus represents the
A. Gametophytic phase in pteridophytes
B. Sporophytic phase of pteridophytes
C. Sporophytic phase in gymnosperms
D. Sporophytic phase in angiosperms

Answer 1

Hint: Alternation of generation happens in ferns. The sporophytic and gametophytic generations are the two separate generations. The spores are released by the sporophyte, while the gametes are released by the gametophyte. The sporophyte is formed when the gametes fuse with the spores, and the gametophyte is formed when the spores fuse with the gametophyte. This cycle continues. In the lifespan of a fern, the prothallus now represents the gametophyte stage.

Complete answer:
Option A: Pteridophytes release their spores, which fall to the ground and mature into prothallus. This is the stage of the gametophyte. Antheridia and archegonia are produced by the prothallus. These are exospheric, flat, green, autotrophic, cordate (heart-shaped), multicellular, short-lived, small reduced, dorsiventral, free-living independent, and nonvascular
So option A is correct.
Option B: The gametophytic generation's plants are all haploid, while the sporophyte generation's plants are all diploid. The gametophyte is represented by the prothallus.
So option B is not correct.
Option C: In a plant's life cycle, sporophyte diploid generation originates from sexual reproduction with gametes and produces spores for asexual reproduction.
So option C is incorrect.
Option D: A pea plant is used to symbolise the life cycle of an angiosperm (genus Pisum). The sporophyte is the dominant generation, although the blooms of the sporophyte produce multicellular male and female gametophytes. The gametophyte thus feeds both the embryo and the mature sporophyte.
So option D is not correct.

So option A is the correct answer.

Note:
Ferns are a vascular plant group that belongs to the Pteridophytes plant kingdom. They reproduce by dispersing spores and do not generate seeds or blooms. They vary from mosses in that they have a vascular system and the sporophyte phase is the most prominent in their life cycle.