Question

cell differentiation starts from – day of conception​

Answer 1

The correct answer is 4.

Explanation:

• After fertilisation of the haploid egg and the haploid sperm the diploid zygote is formed.
• The zygote divides to form a solid clump of sixteen cells called the Morula. These cells are undifferentiated.
• On the fourth day after fertilisation the cells of the morula divides to form  a Blastocyst.
• The Blastocyst is comprised of differentiated cells.
• The Blastocyst is a hollow cellular mass comprising of:

1. Trophoblast, outermost layer, responsible for providing nutrition to the embryo by forming the placenta.
2. Blastocoel, a space filled with a fluid.
3. Inner cell mass, that remains attached to the trophoblast, and is comprised of the stem or germ cells of the embryo.