**Explanation:**

Decomposition is the process by which organic matter breaks down into simpler substances, such as carbon dioxide, water, and minerals. It is a natural process that is essential for nutrient recycling in ecosystems.

Conditions that favor decomposition are important to understand because they can determine the rate at which organic matter decomposes and the types of organisms involved in the process.

The correct answer to the given question is option 'A', which states that high temperature and intermediate humidity favor decomposition. Let's understand why this is the case:

**1. High Temperature:**
- Decomposition is an enzymatic process, meaning it is facilitated by the action of enzymes produced by microorganisms, such as bacteria and fungi.
- Enzymatic reactions are generally more efficient at higher temperatures because they increase the rate of biochemical reactions.
- High temperatures accelerate the metabolic activity of decomposer organisms, leading to faster decomposition rates.

**2. Intermediate Humidity:**
- Decomposer organisms require a certain level of moisture to carry out their metabolic processes effectively.
- If the humidity is too high, the excessive moisture can create an anaerobic environment (lack of oxygen) that is unfavorable for many decomposer organisms.
- If the humidity is too low, the lack of moisture restricts the activity of decomposer organisms.
- Intermediate humidity provides the ideal conditions for decomposer organisms to thrive and efficiently decompose organic matter.

**Conclusion:**
In conclusion, the correct answer to the given question is option 'A' (high temperature and intermediate humidity) because these conditions provide the ideal environment for the activity of decomposer organisms, leading to faster and more efficient decomposition of organic matter.