Not only are these but the lives of some of them dependent...

Not only are these but the lives of some of them dependent on the lives of others. Thus, when due to some reason or another, some of these parts turn weak and die, the other parts too die. Similarly it is the microbes, which reduces man's age and restricts it to seventy or eighty years especially the number of human-beings who die during childhood.

What has ultimately been concluded from tests and experiments is as such: The reason why man dies is not because he has completed seventy, eighty or hundred years but because the external factors enter some of his (internal) parts and kill and destroy them…