Dominant independent haploid plant body is observed inA) Polytrichum B) FernC) Spirogyra D) Salvinia

The dominant independent haploid plant body is observed in A) Polytrichum.

Here's why:

In the life cycle of plants, there are two stages: the haploid (gametophyte) and the diploid (sporophyte). The gametophyte stage produces gametes (sex cells), and the sporophyte stage produces spores.

In most higher plants like ferns (B) and Salvinia (D), the dominant stage is the sporophyte (diploid) stage. However, in some lower plants like mosses and liverworts, the dominant stage is the gametophyte (haploid) stage.

Polytrichum (A) is a type of moss. In mosses, the gametophyte stage is dominant and independent, meaning it can carry out all the necessary functions of the plant.

Spirogyra (C) is a type of green algae, not a plant, and it doesn't have a dominant independent haploid plant body.

So, the correct answer is A) Polytrichum.