Question

Given are diagram showing the different stages in the process of fertilisation of an egg in the human female reproductive tract.
Study the diagrams and answer the question.
Arrange the letters given, each diagram in a logical sequence to show the correct order in the process of fertilisation.

Answer 1

Fertilisation is the fusion of male gamete (sperm) with the female gamete (egg) to form a diploid zygote.

Hence the letters should be arranged in the following order to show the correct order in the process of fertilisation.

D,C,B,A.

D shows an egg cell containing a nucleus.

C shows the egg cell surrounded by many sperms which are trying to enter the egg cell.

B shows the sperm which got succeeded in entering the egg cell and the entry of other sperm cells is blocked by the egg cell.

A shows two nucleus in the egg cell, one of which belongs to the egg cell and the other is of sperm cell. These two nuclei will then fuse to form a diploid nucleus and a zygote will be formed.