Question

Arrange the following in the correct sequence of prenatal stages of development
(A). Conception
(B). Embryo
(C). Fetus
(D). Zygote
Choose the correct answer from the options given below:

• A. (A), (B), (D), (C).
• B. (B), (A), (D), (C).
• C. (A), (D), (B), (C).
• D. (A), (C), (B), (D).

Hint:

To remember the stages of prenatal development:
Conception $\rightarrow$ Zygote (Weeks 0--2) $\rightarrow$ Embryo (Weeks 2--8) $\rightarrow$ Fetus (Week 9--Birth).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Human development begins long before birth, during the prenatal period.
This period spans approximately 38 to 40 weeks, starting from the fertilization of the egg to the birth of the baby.
Prenatal development is divided into three distinct, chronological stages:
1. The Period of the Zygote (Germinal Stage)
2. The Period of the Embryo
3. The Period of the Fetus
Each stage is characterized by specific biological milestones, cell division patterns, and organ development.

Step 2: Detailed Explanation:
Let us trace the correct chronological sequence of these prenatal stages:
1. Conception (A):
This is the starting point of prenatal development, where a single male sperm cell fertilizes a female ovum to form a single, fertilized cell.
Thus, (A) is the first step.
2. Zygote (D):
Immediately following fertilization, the single-celled organism is called a zygote.
The germinal stage (period of the zygote) lasts about two weeks, during which the zygote undergoes rapid cell division (cleavage) as it travels down the fallopian tube and implants into the uterine wall.
Thus, (D) is the second step.
3. Embryo (B):
Following successful implantation, the period of the embryo begins, lasting from week 2 to week 8 of pregnancy.
This is a critical period of rapid growth and organogenesis, where the foundations of all major bodily organs and systems (nervous system, heart, limbs, digestive tract) are established.
Thus, (B) is the third step.
4. Fetus (C):
The period of the fetus begins at week 9 and lasts until birth.
During this final stage, the organ systems grow and refine, the skeletal structure hardens, and the fetus gains weight and prepares for birth.
Thus, (C) is the fourth step.
Therefore, the correct sequence is: Conception (A) \(\rightarrow\) Zygote (D) \(\rightarrow\) Embryo (B) \(\rightarrow\) Fetus (C), which corresponds to option (C).

Step 3: Final Answer:
Consequently, the correct chronological sequence of prenatal development is (A), (D), (B), (C).