Interaction between . . . . . . And certain environmental factors regulate the reproductive processes and the associated behavioural expression of organisms.

Options

A. Enzymes
B. Hormones
C. Vitamins
D. All of the above

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the interaction between a specific factor and environmental factors that regulate reproductive processes and behaviors in organisms.

2. **Identifying the Key Terms**: The key terms in the question are "interaction," "environmental factors," "reproductive processes," and "behavioral expression."

3. **Recognizing the Role of Hormones**: In both plants and animals, hormones play a crucial role in regulating various biological processes, including reproduction. They are responsible for transitions between different life phases.

4. **Defining the Life Phases**: The three main phases of an organism's life cycle are:
- **Juvenile Phase**: Also known as the growth phase, where the organism develops and matures.
- **Reproductive Phase**: The phase where the organism is capable of reproduction.
- **Senescent Phase**: Also known as the old stage, which leads to aging and eventually death.

5. **Connecting Hormones to Environmental Factors**: Hormones interact with environmental factors (like temperature, light, and nutrients) to regulate these life phases. For example, changes in day length can trigger hormonal changes that initiate reproduction in certain species.

6. **Conclusion**: Based on the information, the correct answer to the question is "hormones," as they are the interacting factor that regulates reproductive processes and behaviors in response to environmental changes.

### Final Answer:
The interaction between **hormones** and certain environmental factors regulates the reproductive processes and the associated behavioral expression of organisms.

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