Which is immortal?

Options

A. Plasma cell
B. Germ cell
C. Brain cell
D. Kidney cell

Answer

To determine which type of cell is considered immortal from the given options, we can analyze each option based on their characteristics and lifespan.

### Step-by-Step Solution:

1. **Understanding Immortality in Cells**:
- Immortal cells are those that can divide indefinitely and do not have a fixed lifespan. This means they can continue to replicate without undergoing senescence (aging).

2. **Analyzing the Options**:
- **Plasma Cells**: These are derived from B lymphocytes and are involved in producing antibodies. They have a limited lifespan and eventually die after fulfilling their function.
- **Germ Cells**: These are the reproductive cells (sperm and eggs) that give rise to gametes. Germ cells are considered immortal because they can continue to divide and produce new cells indefinitely.
- **Brain Cells**: Neurons in the brain have a fixed lifespan and do not replicate like other cells. Although some neurogenesis occurs, most neurons do not divide and have a limited lifespan.
- **Kidney Cells**: These cells, like other somatic cells, have a specific lifespan and can undergo cell division, but they do not have the ability to divide indefinitely.

3. **Conclusion**:
- Among the options, only **germ cells** are considered immortal because they do not have a fixed lifespan and can continue to replicate indefinitely.

### Final Answer:
The immortal cell from the options provided is **germ cells**.

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