Character of a stable community is that it
(a) should not show too much variations in year-to-year productivity
(b) must be resistant to occasional natural or man-made disturbances
(c) should be resistant to invasions by alien species
(d) all of these

Options

A. should not show too much variations in year-to-year productivity
B. must be resistant to occasional natural or man-made disturbances
C. should be resistant to invasions by alien species
D. all of these

Explanation

To answer the question regarding the characteristics of a stable community, we will analyze each option provided:

1. **Understanding a Stable Community**:
- A stable community is defined as a self-perpetuating community that exists in harmony with its environment. This means it maintains a balance and does not undergo significant changes over time.

2. **Analyzing Option (a)**:
- Option (a) states that a stable community "should not show too much variations in year-to-year productivity."
- This is true because a stable community typically has consistent productivity levels, indicating stability and resilience.

3. **Analyzing Option (b)**:
- Option (b) mentions that a stable community "must be resistant to occasional natural or man-made disturbances."
- This is also correct as stable communities can withstand disturbances without significant changes to their structure or function.

4. **Analyzing Option (c)**:
- Option (c) claims that a stable community "should be resistant to invasions by alien species."
- This is true as well, since a stable community is often characterized by its ability to resist invasive species that could disrupt the existing balance.

5. **Conclusion**:
- Since all three options (a), (b), and (c) accurately describe characteristics of a stable community, the correct answer is option (d) "all of these."

Thus, the complete answer to the question is:
**(d) all of these**

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