Natural selection leads to evolution due to the way reproduction works. In the example of European moths during the industrial revolution, we can see this clearly. When the industrial revolution was going, there was more pollution, hence darkening the skies and leaving ash. Moths, which before were white with occasional black spots dominated the area until pollution effected their environment. Whiter moths were eaten by bird who could easily see them against the black trees and skies. These moths could no longer reproduce, they were dead. Moths with more black could survive longer to reproduce because they were harder to see. As time went along, the moths turned mostly black, showing an example of evolution.
When cells divide, they make new cells. A single cell divides to make two cells and these two cells then divide to make four cells, and so on. We call this process "cell division" and "cell reproduction," because new cells are formed when old cells divide
Human heart is myogenic becoz it have the tendency to generate impulse by itself. The upper right auricle wall of heart has sino atrium node or SN node which helps in generation of impulse without any external stimulus.
