Test tube baby means a baby born when

Options

A. It is developed in a test tube
B. It is developed through tissue culture method
C. The ovum is fertilized externally and thereafter implanted in the uterus
D. It develops from a non-fertilized ovum

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 known as in vitro fertilization (IVF). This involves fertilizing an egg (ovum) with sperm outside the human body.

2. **Collection of Gametes**:
In the test tube baby process, the female gamete (ovum) is collected from a donor female. This is the first step in the IVF process.

3. **In Vitro Fertilization**:
The collected ovum is placed in a test tube under controlled laboratory conditions, which provide all the necessary nutrients for the survival of the gamete. This is referred to as in vitro conditions.

4. **Fertilization**:
The female gamete (ovum) is then fertilized with the male gamete (sperm) in the test tube. This external fertilization leads to the formation of a zygote, which is a diploid cell.

5. **Implantation**:
After the zygote is formed, it is then implanted into the uterus of the female. This step is crucial as the development of the embryo occurs inside the uterus.

6. **Conclusion**:
Based on the above steps, the correct definition of a test tube baby is that it is a baby born after the ovum is fertilized externally (in a test tube) and then implanted into the uterus.

**Final Answer**: The correct option is: "the ovum is fertilized externally and thereafter implanted in the uterus."

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