Answer:
because harmful substances often chemicals or microorganisms contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment.
Explanation:
Hope This Helps!!!
Answer:
Migration boosts the working-age population. Migrants arrive with skills and contribute to human capital development of receiving countries. Migrants also contribute to technological progress. Understanding these impacts is important if our societies are to usefully debate the role of migration
Answer:
because many ships transport and Sell There which Makes A lot of Oil spills accidents and wars Over land
The answer is tectonic plates
Maybe under your bed hope that helped :)