Which statement best describes a negative effect of human activity on Africa’s waterways?

O The use of river transportation has harmed water quality.

Explanation:

The rest of the options have effects that would have happened on their own over time anyways. Some of them Ern't much of our fault in fact. River transportation has had a dramatic impact though, and it is something humans are Indeed responsible for

The excretory system is a passive biological system that removes excess and unnecessary materials from the body, so as to help maintain homeostasis and prevent damage. The main organs involved in waste management are the skin ETC.