Select the correct Statement :

Options

A. The first movements of foetus and appearance of hairs on the head are usually observed during sixth month of pregnancy.
B. The mammary glands of the female undergo differentiation before puberty and start producing milk at the end of pregnancy.
C. Trophoblast cells contain specialised stem cells which have the potency to give rise all the tissue and organs.
D. After implantation , finger-like projection appears on the trophoblast which is surrounded by uterine tissue and meternal blood.

Answer

To solve the question, we need to evaluate each statement provided and determine which one is correct. Let's break it down step by step.

### Step 1: Evaluate the First Statement
**Statement:** The first movement of the fetus and the appearance of hairs on the head are usually observed during the 6th month of pregnancy.

**Evaluation:** This statement is incorrect. The first fetal movements, known as "quickening," and the appearance of hair on the fetus typically occur around the 5th month of pregnancy, not the 6th.

### Step 2: Evaluate the Second Statement
**Statement:** The mammary glands of the female undergo differentiation before puberty and start producing milk at the end of pregnancy.

**Evaluation:** This statement is also incorrect. The mammary glands undergo differentiation primarily during pregnancy, and they start producing milk after childbirth, a process known as lactation, not at the end of pregnancy.

### Step 3: Evaluate the Third Statement
**Statement:** Trophoblast cells contain specialized stem cells which have the potency to give rise to all the tissues and organs.

**Evaluation:** This statement is incorrect. While trophoblast cells play a crucial role in implantation and the formation of the placenta, they do not have the potency to give rise to all tissues and organs. That characteristic is typically associated with embryonic stem cells.

### Step 4: Evaluate the Fourth Statement
**Statement:** After implantation, finger-like projections appear on the trophoblast, which is surrounded by the uterine tissue and maternal blood.

**Evaluation:** This statement is correct. After implantation, the trophoblast develops finger-like projections called chorionic villi, which invade the uterine tissue and are surrounded by maternal blood. This structure facilitates the exchange of nutrients and waste between the mother and the developing fetus.

### Conclusion
The correct statement is the fourth one.

### Final Answer
**The correct statement is:** After implantation, finger-like projections appear on the trophoblast, which is surrounded by the uterine tissue and maternal blood.

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