Single filament of Nostoc without mucilage sheath is known as

Options

A. Mycelium
B. Trichome
C. Hypha
D. Colony.

Answer

To solve the question regarding the single filament of Nostoc without the mucilage sheath, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nostoc**:
- Nostoc is a type of filamentous cyanobacteria that performs photosynthesis. It typically exists in filamentous forms surrounded by a mucilaginous sheath.

2. **Identifying the Structure**:
- In Nostoc, the filamentous structure consists of cells, including specialized cells called heterocysts, which are responsible for nitrogen fixation.

3. **Defining the Term**:
- The question specifically asks for the term that refers to a single filament of Nostoc when it is not surrounded by the mucilaginous sheath.

4. **Choosing the Correct Term**:
- The correct term for a single filament of Nostoc without the mucilaginous sheath is "trichome". This term is used specifically for filamentous structures in cyanobacteria.

5. **Eliminating Other Options**:
- Other terms like "mycelium" refer to fungal structures (a network of hyphae) and "colony" refers to a group of organisms, which do not apply to a single filament.

6. **Final Answer**:
- Therefore, the answer to the question is "trichome".