Correct statement with reference to a test-tube baby is

Options

A. the fertilised egg is placed in the womb of the mother where the gastrula period is completed
B. unfertilised egg is placed in the womb and allowed to grow parthenogenetically
C. a prematurely born baby is reared in an incubator
D. fertilised egg is taken out and grown in a large test-tube

Answer

### Step-by-Step Solution:

1. **Understanding the Concept of Test-Tube Baby**:
- A test-tube baby refers to a baby that is conceived through a process called In Vitro Fertilization (IVF). This process involves fertilizing an egg with sperm outside the body.

2. **IVF Process**:
- In IVF, eggs (ova) are retrieved from the female's ovaries and sperm is collected from the male.
- The fertilization of the egg by the sperm occurs in a laboratory setting, not inside the female's body.

3. **Formation of Zygote**:
- After fertilization, a zygote is formed. This zygote is then cultured in a controlled environment until it develops into an embryo.

4. **Embryo Development**:
- The embryo continues to develop until it reaches the eight-celled stage, known as the blastomere stage.

5. **Implantation**:
- Once the embryo reaches the appropriate developmental stage, it is implanted into the uterus of the female. This is where it will continue to grow and develop into a fetus.

6. **Birth of the Baby**:
- After approximately nine months of gestation, a healthy baby is born.

7. **Evaluating the Statements**:
- The first statement claims that the fertilized egg is placed in the womb of the mother where the gastrula period is completed. This is correct because the fertilized egg (embryo) is indeed placed in the womb after fertilization occurs outside the body.
- The second statement about an unfertilized egg being placed in the womb is incorrect, as fertilization must occur for a test-tube baby.
- The third statement regarding a prematurely born baby being reared in an incubator is also incorrect in the context of test-tube babies.
- The fourth statement about the fertilized egg being grown in a large test tube is partially correct, but it does not accurately describe the implantation process.

8. **Conclusion**:
- The correct statement regarding a test-tube baby is that the fertilized egg is placed in the womb of the mother where the gastrula period is completed.