Estriys cycle is indication of

Options

A. Breeding period
B. Estrogen secretion
C. Pregnancy
D. Menopause

Answer

### Step-by-Step Solution:

1. **Understanding the Estrous Cycle**: The estrous cycle refers to the regular reproductive cycle in female mammals, particularly in non-primate species. It indicates the periods of receptivity to mating and is characterized by hormonal changes that prepare the female for potential pregnancy.

2. **Identifying the Context**: The estrous cycle is primarily observed in animals, especially in livestock such as cattle, dogs, and cats. It is different from the menstrual cycle seen in humans.

3. **Analyzing the Options**: The question provides four options:
- Breeding period
- Estrogen secretion
- Pregnancy
- Menopause

4. **Eliminating Irrelevant Options**:
- **Estrogen secretion**: While estrogen is involved in the estrous cycle, it does not define it.
- **Pregnancy**: This occurs after mating but is not what the estrous cycle itself indicates.
- **Menopause**: This is a human-specific term indicating the end of reproductive capability, which does not apply to the estrous cycle.

5. **Identifying the Correct Answer**: The estrous cycle indicates the breeding period, as it represents the times when a female is receptive to mating and can conceive.

6. **Conclusion**: Therefore, the estrous cycle is an indication of the breeding period in animals.