Blood is discharged from the uterus in

Options

A. oestrous cycle
B. menstrual cycle
C. cardiac cycle
D. urea circle

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the process in which blood is discharged from the uterus. This is a biological process that occurs in females.

2. **Identifying the Options**: The options provided are:
- Estrous cycle
- Menstrual cycle
- Cardiac cycle
- Urea cycle

3. **Analyzing Each Option**:
- **Estrous Cycle**: This cycle occurs in many female mammals and is characterized by periods of receptivity to mating, but it does not involve the discharge of blood from the uterus.
- **Menstrual Cycle**: This cycle occurs in humans and some other primates. It involves the shedding of the uterine lining if fertilization does not occur, leading to the discharge of blood.
- **Cardiac Cycle**: This refers to the sequence of events in one heartbeat, including the pumping of blood by the heart. It is not related to the uterus.
- **Urea Cycle**: This is a metabolic pathway that converts ammonia to urea for excretion and is unrelated to the reproductive system.

4. **Conclusion**: The correct answer is the **Menstrual Cycle** (option B), as it specifically involves the discharge of blood from the uterus when the egg is not fertilized.

5. **Final Answer**: Blood is discharged from the uterus in the **Menstrual Cycle**.

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