The term explant refers:

Options

A. A plant part used for tissue culture
B. An unorganised mass of cells
C. A complete hybrid plant
D. A waste part of plant

Answer

### Step-by-Step Solution:

1. **Understanding the Term "Explant":**
- The term "explant" refers to a specific part of a plant that is used in tissue culture. This can be any part of the plant, such as leaves, stems, or roots.

2. **Role of Explant in Tissue Culture:**
- In tissue culture, the explant is taken from a plant and placed in a sterile environment with a special nutrient medium. This medium contains all the necessary nutrients and vitamins required for the growth of the plant tissue.

3. **Process of Micropropagation:**
- The explant is cultured under sterile conditions, allowing it to grow into a complete plant. This process is known as micropropagation, where thousands of plants can be produced from a single explant.

4. **Genetic Identity of the New Plants:**
- The plants that develop from the explant through micropropagation are genetically identical to the original parent plant. These genetically identical plants are referred to as "soma clones."

5. **Elimination of Incorrect Options:**
- The other options provided (unorganized mass of cells, complete hybrid plant, waste part of the plant) do not accurately describe the term "explant."
- An unorganized mass of cells is called "callus."
- A complete hybrid plant is not referred to as an explant.
- A waste part of the plant does not have any relevance to tissue culture.

6. **Conclusion:**
- Therefore, the correct definition of the term "explant" is a plant part used for tissue culture.

### Final Answer:
The term explant refers to a plant part used for tissue culture.

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