The burning of fossil fuels provides energy for humans to use, but it also can have negative effects. For example, when large power plants burn fossil fuels, certain chemicals are released in the atmosphere that react with water vapor, resulting in acidic precipitation. This phenomenon is known as acid rain. Acid rain has had an adverse effect on ecosystem diversity throughout the world.

Which of the following would best decrease acid rain levels and reduce the human pollution impact on the environment?
A.
regulation of human outdoor activity
B.
chemical treatment of the soil that has been affected by acid rain
C.
chemical treatment of the water that has been affected by acid rain
D.
regulation of factory emissions

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.