A polysachharide employed in tissue culture is

Options

A. Cellulose
B. Starch
C. Glycogen
D. Agar-agar.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a polysaccharide that is used in tissue culture. Tissue culture is a technique used to grow cells or tissues in a controlled environment outside of their natural environment.

2. **Identifying the Options**: The options provided are:
- Cellulose
- Starch
- Glycogen
- Agar-agar

3. **Analyzing Each Option**:
- **Cellulose**: This is a structural polysaccharide found in the cell walls of plants. It is not typically used in tissue culture.
- **Starch**: This is a storage polysaccharide in plants, primarily used for energy storage. It is not used in tissue culture.
- **Glycogen**: This is a storage polysaccharide in animals, also not used in tissue culture.
- **Agar-agar**: This is a gelatinous substance derived from red algae. It is a polysaccharide that is commonly used as a solidifying agent in microbiological culture media.

4. **Conclusion**: After analyzing the options, agar-agar is identified as the polysaccharide employed in tissue culture due to its properties as a solidifying and emulsifying agent.

5. **Final Answer**: The correct answer is **agar-agar**.

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