Which of the following animals show menstrual cycle ?

Options

A. Gorillas and chimpanzees
B. Monkeys and humans
C. Orangutans and monkeys
D. All of these

Explanation

**Step-by-Step Solution:**

1. **Understanding the Menstrual Cycle**: The menstrual cycle is a reproductive cycle that occurs in female primates, including humans. It typically lasts about 28 days and involves the preparation of the body for potential pregnancy.

2. **Types of Reproductive Cycles**: There are two main types of reproductive cycles in mammals:
- **Menstrual Cycle**: This cycle occurs in primates and involves shedding of the uterine lining if fertilization does not occur.
- **Oestrus Cycle**: This cycle occurs in non-primates, where females are only receptive to mating during specific periods known as "estrus."

3. **Identifying Primates**: Primates are a group of mammals that include humans, apes, monkeys, and others. They are characterized by their higher cognitive abilities and social structures.

4. **Analyzing the Options**:
- **Gorillas and Chimpanzees**: Both are primates.
- **Monkeys and Humans**: Both are primates.
- **Orangutans and Monkeys**: Both are primates.
- **All of These**: Since all the groups listed are primates, they all exhibit the menstrual cycle.

5. **Conclusion**: Since all the options provided (gorillas and chimpanzees, monkeys and humans, orangutans and monkeys) are primates, the correct answer is that all of these animals show a menstrual cycle.

**Final Answer**: All of these animals show a menstrual cycle.

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