Explain why acid precipitation is a source of international conflict and why international cooperation is necessary to resolve the problem.

Is a source of international conflict because, as it falls downwind, the area in which it accumulated is not necessarily the area that will be damaged. So countries must work together to reduce the problem because they are damaging one another's environments.

Sir Charles Lyell's work help scientists by providing an understanding that most changes on earth’s surface happen slowly. Option C is correct.

Sir Charles Lyell is a very known lawyer that diverted himself to the field of Geology. Hi is well known for writing his book, "Principles of Geology". In this book, he explained that valleys were formed from the gradual process of formation and that the Earth went throught periodic changes throughout.