Question

The most primitive vascular plants are
a. Cycas
b. Ferns
c. Moss
d. Brown algae

Answer 1

Hint: Vascular plants are the large group of plants which live on the land, they are termed as Tracheophytes, they had specialized tissues, which are xylem, it is lignified tissue for the conduction of water and minerals. And non lignified tissue for conduction of products produced during photosynthesis

Complete answer:
- So many plants have come under the Tracheophytes which include angiosperms, gymnosperms and ferns, and horsetails, etc.
- Among those, primitive vascular plants come under the pteridophytes. They are commonly called ferns.
- Ferns are usually well-differentiated which means they have well-developed roots, stems and all but when to come to life cycle it occurs by the spore dispersal, hence it is considered as the most primitive plant.
- It is a split between the free-living gametophyte and sporophyte phases. When coming to the life cycle of pteridophytes, it has both phases such as gametophyte and sporophyte, the gametophyte is very primitive and underdeveloped and the sporophyte is very well developed.
- So in pteridophytes, sporophytes are dominated in nature.
- When going to the other options, such as cycas it belongs to gymnosperms, they have well-developed structures and they also produce seeds, so they won’t come under primitive plants.
- Mosses belong to bryophytes, these plants also have the well-differentiated stems and leaves but they don’t have well-differentiated vascular tissues.
- Brown algae also do not have the well-differentiated plant body and vascular tissue and they belong to thallophytes.

Hence, The correct answer is option (B).

Note: All of the primitive plants such as algae-like blue, green, red and ferns, mosses all of these plants have alternate life cycles consisting of gametophyte and sporophyte phases, but in all of this embryo is not formed.