Rootless, stem-less and leafless plants are:

Explanation

The correct answer is Liverworts. Liverworts are the simplest form of non-vascular plants and lack true roots, stems, or leaves. They attach to surfaces using rhizoids and reproduce through spores.Mosses, while also non-vascular, have a more complex structure with a pseudo-stem and small leaves. Psilopsida, on the other hand, are primitive vascular plants, and onions are fully developed vascular plants with a distinct structure and seed-based reproduction.