The rhizoid of liverwort is

Analyze the question: It asks about the structure of the rhizoid in a liverwort (a bryophyte, e.g., Marchantia).

Explain the concept: Rhizoids are root-like structures that anchor bryophytes to the substrate and absorb water. Bryophytes have no true roots, so they use rhizoids instead.

• In liverworts, rhizoids are unicellular (each is a single elongated cell) and unbranched.
• In mosses, rhizoids are multicellular and branched, with oblique cross-walls separating the cells.

This is the main difference between liverwort and moss rhizoids, and examiners like to test it.

Step-by-step solution:

1. Identify the organism: liverwort, a bryophyte of the class Hepaticae.
2. Recall its rhizoid structure: each rhizoid is a single-celled, thread-like outgrowth from the lower surface of the thallus.
3. Check for branching: liverwort rhizoids are simple and unbranched.
4. Match the options: • B (multicellular, branched) describes moss rhizoids. • C (unicellular, branched) is not a standard description. • D (multicellular, unbranched) is not a standard description. • A (unicellular, unbranched) matches liverworts.

Answer: A. unicellular and unbranched

Exam tip: Remember "Liverwort = Lone (single) cell, Linear (unbranched)". The moss has many cells and branches. The simpler plant, the liverwort, has the simpler rhizoid.