Answer:
its the level of acid in substances
you put the amount of a item into a cup and add water.
Explanation:
I think D is the right answer.
The answer is:
For the farmers own needs
The cyanobacteria changed the composition of the earth’s atmosphere by evolving oxygen in what is referred to as the Great Oxygenation Event. This also allowed the ozone to be formed and block off most of the UV rays that are destructive to genetic material. Life was, therefore, also able to exist on land other than in water.