Under favourable conditions euglena reproduces by

Options

A. Transverse binary fission
B. Longitudinal binary fission
C. Palmella stage
D. None

Answer

### Step-by-Step Solution:

1. **Understanding Euglena**: Euglena is a unicellular organism that can perform photosynthesis and is classified under the kingdom Protista. It is known for its ability to adapt to various environmental conditions.

2. **Identifying Favorable Conditions**: Favorable conditions for Euglena include adequate water, suitable temperature, and sufficient food supply. These conditions promote active growth and reproduction.

3. **Reproductive Method**: Under these favorable conditions, Euglena reproduces asexually. The primary method of reproduction in Euglena is binary fission.

4. **Types of Binary Fission**: There are two types of binary fission: transverse and longitudinal. In transverse binary fission, the organism divides across its width, while in longitudinal binary fission, it divides along its length.

5. **Correct Type of Binary Fission**: During favorable conditions, Euglena reproduces by **longitudinal binary fission**. This means the organism divides into two equal halves along its length, resulting in two identical daughter cells.

6. **Nuclear Division**: The nucleus of the Euglena divides by the process of mitosis before the organism splits into two, ensuring that each daughter cell receives a complete set of genetic material.

7. **Conclusion**: After analyzing the options provided in the question, the correct answer is **longitudinal binary fission**.

### Final Answer:
Euglena reproduces by **longitudinal binary fission** under favorable conditions.

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