Question

Arrange the following events in the correct order pertaining to fertilization in the human reproductive system.
(A) The blastocyst becomes embedded in the endometrium. 
(B) Finger-like projections appear on the trophoblast called chorionic villi. 
(C) The blastomeres are arranged into trophoblast and the inner cell mass. 
(D) The zygote divides mitotically and transforms into an embryo with 8-16 blastomeres, called a morula. 
 

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

Hint:

Fertilization involves complex processes, starting with the formation of the morula and ending with the implantation of the blastocyst into the endometrium.

Answer 1

The Correct Option is A

Step 1: Understand the process of fertilization.
- (D) The zygote divides mitotically, forming the morula (a cluster of 8-16 blastomeres).
- (C) The morula further divides, and the blastomeres are arranged into trophoblast and the inner cell mass.
- (A) The blastocyst then becomes embedded into the endometrium.
- (B) Finger-like projections, known as chorionic villi, appear on the trophoblast.
Conclusion:
The correct order is:
(D) → (C) → (A) → (B).
Final Answer: \[ \boxed{\text{The correct order is (D), (C), (A), (B).}} \]