Question

In the human female, the fertilized eggs get implanted in the uterus
A. After two months of fertilization
B. After one month of fertilization
C. After 3 weeks of fertilization
D. After about 7 days of fertilization.

Answer 1

Hint: In humans, internal fertilization occurs where the male and female gametes fuse and the development of the embryo takes place inside the female body. The zygote formed after fertilization starts to divide and travels into the uterus where it burrows itself into the wall of the uterine. This process is called implantation.

Complete answer: The fertilization of the egg takes place somewhat in the middle of the fallopian tube.
The formed zygote undergoes continuous division and starts to travel and reaches the uterus in 4-5 days and the zygote is referred to as the morula.
In the uterus, the morula becomes a blastocyst and then gets implanted into the uterine wall in 7-8 days.
After 3 weeks of fertilization, the zygote is about 0.1mm in length.
After one month of fertilization, formation of the amniotic sac occurs which helps in the growth of the embryo. There is also the development of the placenta.
After two months of fertilization, the embryo is about 4-5 inches long. At this stage, the basic heart beating and development of the circulatory system occur. The umbilical cord also develops.
 In the human female, the fertilized eggs get implanted in the uterus after 7 days of fertilization.
Hence, the correct answer is option (D).

Note: The time taken for implantation will differ from person to person. For some, it will be 7 days but for some, it will take more than a week. The implantation in the uterine wall is mainly done to derive nutrition for the developing embryo from the mother.