We require to keep our water supply clean because we imbibe that water. If our water supply wasn't unsullied, we would die of dehydration. Another reason is that without water, all the crops would die and we wouldn't have any aliment to victual and so we would withal die of hunger.
Answer:
ok this is point less but whatever you want
It is milk because milk has lactose
Answer: The study of plant varieties.
Explanation:
This question relates to the studies that Gregor Mendel, founder of modern genetics, performed at the University of Vienna.
Experimenting on pea plants, Gregor Mendel was able to establish a lot of the rules of heredity that we know today even though his research was not fully appreciated or understood during his own life.
He credited the study of plant varieties to have been most crucial to his final analysis because farmers had been crossbreeding varieties for millennia to bring about better traits in plants.