All humans on earth today may differ widely in their facial features, colour, height, etc. Yet, they belong to a single species Homo sapiens. Give one reason why they are not considered belonging to different species.
You would have noticed that you share some characteristics (such as hair, nose, eyes etc.) from your mother and some from your father. But, if you have seen a plant nursery, all the rose plants of the same color appear to be very similar to each other.
Which type of reproduction do you think humans follow and plants in the nursery follow?
Which part of the human eye is responsible of rendering different eye colour for different human beings?