Oestrus cycle is seen in

Options

A. chimpanzee.
B. gorilla.
C. cows.
D. More than one option is correct

Answer

To solve the question "Oestrus cycle is seen in," we need to analyze the options provided and understand the definitions of the terms involved.

### Step-by-Step Solution:

1. **Understanding Oestrus Cycle**:
- The oestrus cycle refers to the reproductive cycle in non-primate mammals. It involves cyclical changes in the reproductive hormones and activities of the ovaries and reproductive tract.

2. **Identifying Non-Primate Mammals**:
- Non-primate mammals include species such as cows, sheep, dogs, and deer. These animals exhibit the oestrus cycle.

3. **Identifying Primate Mammals**:
- Primates, which include monkeys, apes, chimpanzees, gorillas, and humans, do not have an oestrus cycle. Instead, they have a menstrual cycle, which is a different type of reproductive cycle characterized by the shedding of the uterine lining.

4. **Analyzing the Options**:
- The options provided are chimpanzee, gorilla, cows, and "more than one option is correct."
- Since cows are non-primate mammals, they exhibit the oestrus cycle. In contrast, chimpanzees and gorillas are primates and do not exhibit the oestrus cycle; they have a menstrual cycle.

5. **Conclusion**:
- The only correct answer from the options provided is "cows," as they are the only animals listed that exhibit the oestrus cycle.

### Final Answer:
The oestrus cycle is seen in **cows**.