which of the following statements is incorrect?

Options

A. placenta is formed by structures contributes by both mother and fetus
B. TORCH infections are major cause of miscarriage in first trimester
C. Relaxin facilitates parturition by softening bones of public symphysis
D. there is no mixing of material and foetal blood occur during foetal development

Answer

To determine which statement is incorrect, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- The first statement claims that the placenta is formed by structures contributed by both the mother and the fetus.
- **Evaluation:** This statement is correct. The placenta is indeed formed from both maternal tissues (decidua) and fetal tissues (chorion).

2. **Analyze the Second Statement:**
- The second statement mentions that TORCH infections are a major cause of miscarriage in the first trimester.
- **Evaluation:** This statement is also correct. TORCH infections (Toxoplasmosis, Other, Rubella, Cytomegalovirus, and Herpes Simplex Virus) can lead to complications during pregnancy, including miscarriage, particularly in the first trimester.

3. **Analyze the Third Statement:**
- The third statement states that Relaxin facilitates parturition by softening the bones of the pubic symphysis.
- **Evaluation:** This statement is incorrect. While Relaxin does play a role in pregnancy, it is Oxytocin that primarily facilitates parturition by causing contractions and helping to soften the pubic symphysis.

4. **Analyze the Fourth Statement:**
- The fourth statement asserts that there is no mixing of materials between maternal and fetal blood during fetal development.
- **Evaluation:** This statement is correct. During normal pregnancy, maternal and fetal blood do not mix; they are separated by the placental barrier.

### Conclusion:
After evaluating all statements, the incorrect statement is the third one, which incorrectly attributes the role of facilitating parturition to Relaxin instead of Oxytocin.

### Final Answer:
The incorrect statement is: **"Relaxin facilitates parturition by softening bones of the pubic symphysis."**

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