Which of the following contributes to the formation of placenta?

Options

A. Uterus and ovary
B. Ovary and embryo
C. Uterus and fallopian tube
D. Embryo and uterus

Answer

To determine which of the following options contributes to the formation of the placenta, we can analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding the Placenta**:
- The placenta is an organ that develops in the uterus during pregnancy. It plays a crucial role in providing nutrients and oxygen to the growing fetus and removing waste products.

2. **Evaluating the Options**:
- **Option 1: Uterus and Ovary**:
- The uterus is involved in the formation of the placenta, but the ovary is primarily responsible for producing egg cells. Therefore, this option is incorrect.

- **Option 2: Ovary and Embryo**:
- While the embryo is essential for the formation of the placenta, the ovary does not contribute to the placenta's formation; it only produces the egg. Hence, this option is also incorrect.

- **Option 3: Uterus and Fallopian Tube**:
- The uterus contributes to the formation of the placenta, but the fallopian tube is involved in the transport of the egg and sperm, providing an environment for fertilization, not for placenta formation. Thus, this option is incorrect.

- **Option 4: Embryo and Uterus**:
- Both the embryo and the uterus contribute to the formation of the placenta. The embryo develops into the fetus and is essential for the placenta's development, while the uterus provides the necessary environment for the placenta to form. Therefore, this option is correct.

3. **Conclusion**:
- The correct answer is **Embryo and Uterus**, as both contribute to the formation of the placenta.