It is important to understand because it's the way all cells reproduce (except sperm and egg cells, they do meiosis), and our cells are the essential parts of our whole being.
Yes of course!
In the most catastrophic case, it can kill hundreds of thousands through hurricanes and the things that come with hurricanes.
Droughts can cause death by both dehydration and starvation if the rain is the only dependable source of arrogation
Too much rain causes floods which can be fatal too
I would say a so I would so do a

Actually Welcome to the Concept of the Genes.
Basically a Polygenetic trait is controlled by two or more genes.
Examples of human polygenic inheritance are height, skin color, eye color and weight. Polygenes exist in other organisms, as well.