Question

Choose the correct answer:

At which of the following stages the implantation in uterus takes place?

• A. 8 cell stage
• B. Morula
• C. Blastocyst
• D. Late gastrula

Answer 1

The correct option is C

Blastocyst

The correct option is C.

Explanation of the correct option:

1. After fertilization in the fallopian tubes, the zygote moves towards the uterus.
2. Within 4 - 16 days after fertilization, blastocyst is formed.
3. This blastocyst gets implanted in the thicker inner wall of the uterus.
4. This process is called implantation.

Explanation of the incorrect options:

Option A: During the 8 - cell stage, the zygote is in the fallopian tubes.

Option B: Morula is also formed in the fallopian tubes through further division of the 8 - cell stage.

Option D: Blastocyst on further differentiation forms the gastrula.

Hence, the implantation occurs at the blastocyst stage.