Rhizoids in Marchantia are

Options

A. Unicellular smooth-walled
B. Unicellular tuberculate
C. Both smooth-walled and tuberculate unicellular
D. Multicellular smooth-walled and tuberculate.

Answer

### Step-by-Step Solution:

1. **Identify the Organism**:
- The question refers to rhizoids in Marchantia, which is a genus of liverworts belonging to the group Bryophytes.

2. **Understand the Structure of Bryophytes**:
- Bryophytes are non-vascular plants that have a thalloid body structure, meaning they do not have true roots, stems, or leaves. Instead, they possess root-like structures known as rhizoids.

3. **Describe the Thallus of Marchantia**:
- The thallus of Marchantia is dorsi-ventral, flattened, and dichotomously branched. It typically measures 2 to 10 cm in length and has an apical notch at the tips of its lobes.

4. **Examine the Rhizoids**:
- Rhizoids in Marchantia are found on the ventral surface of the thallus. They are unicellular and can be classified into two types:
- **Smooth-walled Rhizoids**: These are primarily for anchorage.
- **Tuberculate Rhizoids**: These are involved in capillary conduction.

5. **Determine the Characteristics of Rhizoids**:
- The rhizoids are arranged in 4 to 6 rows on the lower surface of the thallus. They serve different functions, with smooth-walled rhizoids providing stability and tuberculate rhizoids aiding in water and nutrient conduction.

6. **Select the Correct Answer**:
- Given the options, the correct answer would include the characteristics of rhizoids being unicellular and having both smooth-walled and tuberculate types. The best option is one that encompasses both types of rhizoids.

### Final Answer:
The rhizoids in Marchantia are **unicellular and can be either smooth-walled (for anchorage) or tuberculate (for conduction)**. The best option that includes both characteristics is option number three.

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