Question

Fill in the blanks:
(j) Zygote divides to form which is implanted in uterus.

Answer 1

1: Introduction
The zygote is a unicellular diploid cell that undergoes cleavage as it travels from the site of fertilisation in the fallopian tube to the uterus. Cleavage is a type of cell division wherein the cell does not increase in mass,but it divides to form multiple smaller cells within one large single cell. These smaller cells are called blastomeres.

2: Development of zygote
The zygote undergoes cleavage and give rise to 2 celled stage, 4 celled stage, 8 celled stage and 16 celled stage. Once it reaches the 16 celled stage, the blastomeres rearrange as outer trophoblast and inner cell mass. During this stage a cavity called blastocoel develops. The structure thus formed is called blastocyst. This blastocyst embeds in the endometrial lining of the uterus giving rise to the embryo. This process is called implantation
Thus the zygote divides and eventually forms a blastocyst that is implanted in the uterus.