For which of the following organisms there is no natural death ?

Options

A. Bacteria reproducing by sporulation
B. Yeast reproducing by budding
C. Unicellular organisms reproducing by spores
D. Unicellular organisms reproducing by binary fission

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks which organism does not experience natural death. This implies that we need to identify organisms that can reproduce indefinitely without dying.

2. **Analyze Each Option**:
- **Option A: Bacteria reproducing by sporulation**: Bacteria can reproduce asexually by forming spores, especially in unfavorable conditions. However, they do undergo natural death after a certain period. Therefore, this option is incorrect.

- **Option B: Yeast reproducing by budding**: Yeast reproduces asexually through budding, where a new organism grows from the parent. Eventually, the parent yeast does die, making this option incorrect as well.

- **Option C: Unicellular organisms reproducing by spores**: Similar to bacteria, unicellular organisms that reproduce by spores also undergo natural death. Thus, this option is incorrect.

- **Option D: Unicellular organisms reproducing by binary fission**: In binary fission, the parent organism divides into two identical offspring. The parent does not die; instead, it continues to reproduce, effectively leading to a scenario where the original organism does not experience natural death. Therefore, this option is correct.

3. **Conclusion**: After analyzing all the options, the organism that does not experience natural death is **Option D: Unicellular organisms reproducing by binary fission**.

**Final Answer**: D. Unicellular organisms reproducing by binary fission.

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