The rate of secondary succession is faster than primary succession because.

Options

A. soil or sediment is already present
B. water is availbale in large quantity
C. climax community is already present
D. pH of sol is favorable.

Answer

To answer the question, "The rate of secondary succession is faster than primary succession because," we need to understand the fundamental differences between primary and secondary succession.

### Step-by-Step Solution:

1. **Definition of Succession**: Succession refers to the series of changes in an ecosystem that lead to the establishment of a stable community. It can be categorized into two types: primary succession and secondary succession.

2. **Understanding Primary Succession**: Primary succession occurs in an area where there is no soil or sediment present, such as on bare rock after a volcanic eruption or glacial retreat. This type of succession starts from scratch, meaning that the establishment of soil and the initial colonization by organisms must occur before a stable ecosystem can develop. This process is typically slow because it involves the gradual accumulation of organic material and soil formation.

3. **Understanding Secondary Succession**: Secondary succession, on the other hand, takes place in an area where an existing ecosystem has been disturbed or destroyed but where soil and sediment are still present. This could happen after events like forest fires, floods, or human activities that disrupt the ecosystem. Since the soil and some organisms are already present, the recovery and recolonization of the area can occur more rapidly.

4. **Key Reason for Faster Rate of Secondary Succession**: The primary reason that secondary succession is faster than primary succession is that the soil or sediment is already present in the environment where secondary succession occurs. This existing soil contains nutrients and microorganisms that facilitate quicker plant growth and the re-establishment of the ecosystem.

5. **Evaluating the Options**:
- **Soil or sediment is already present**: This is true and is the main reason for the faster rate of secondary succession.
- **Water is available in large quantity**: While water is important, it alone does not account for the speed of succession.
- **Climax community is already present**: This is incorrect; a climax community is not present in secondary succession, as the ecosystem has been disrupted.
- **pH of soil is favorable**: While pH can influence the types of organisms that can thrive, it is not the primary reason for the speed of succession.

6. **Conclusion**: Therefore, the correct answer is that the rate of secondary succession is faster than primary succession because soil or sediment is already present.