Species that invade an area in secondary succession depend on

Options

A. Condition of soil
B. Availability of water
C. Seeds/propafules present in the soil
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Secondary Succession**:
- Secondary succession occurs in an area where a disturbance has destroyed an existing ecosystem but left the soil intact. This can happen after events like forest fires, floods, or human activities.

2. **Factors Influencing Invasion of Species**:
- The species that invade an area during secondary succession depend on several critical factors:
- **Condition of Soil**: The soil must have the right nutrients and structure to support new plant growth. This includes the presence of humus, which is essential for retaining moisture and providing nutrients.
- **Availability of Water**: Water is crucial for the survival of all living organisms. Without sufficient water, plants cannot grow, and consequently, other organisms that depend on plants for food will also struggle to survive.
- **Seeds and Propagules**: The presence of seeds or other reproductive structures (propagules) in the soil is necessary for new plant species to establish themselves. These seeds can come from the surrounding areas or may remain dormant in the soil.

3. **Conclusion**:
- Since all the mentioned factors (condition of soil, availability of water, and presence of seeds) are essential for species to invade an area during secondary succession, the correct answer is "all of the above".

**Final Answer**: All of the above.

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