In some women, oviducts are blocked. These women are unable to bear babies because sperms cannot reach the egg for fertilisation. The doctors advise IVF (invitro fertilisation) in such cases. Below are given some steps of the procedure. Select the INCORRECT step.

Correct option is A

The correct answer is (a) Zygote is kept outside and development takes place in a test tube

Zygote is kept outside, and development takes place in a test tube:

• This is incorrect. In IVF, the zygote is not allowed to develop fully outside the body. Only early embryonic development (up to a few days) occurs in the lab. It is then transferred to the uterus for further development.
  

Fusion of egg and sperms is done outside the body:

• This is correct and is the fundamental step of IVF. Fertilization happens in a lab, outside the body.

Complete development takes place in the uterus:

• This is correct. Once the embryo is transferred to the uterus, it undergoes implantation and completes development naturally.
  

Zygote is formed and after a week placed in the uterus:

• This is correct. The zygote is cultured for a few days (up to the blastocyst stage, about 5–6 days) before being transferred to the uterus.