You could have made sure the books were the same weight and your friends could have done it at the same time as you
Answer:
The answer is A.
Explanation:
To test if the selenium from the mine has an effect on the fish living in the lake which i assume is close to the mine, testing the tissue of the fish from that lake and comparing it to the selenium levels of the fish from a nearby lake would be a testable hypothesis because there is a comparable aspect and there should be a difference in the numbers between the fish from the two lakes because of their distance to the mine.
I hope this answer helps.
All energy sources have some impact on our environment. Fossil fuels—coal, oil, and natural gas—do substantially more harm than renewable energy sources by most measures, including air and water pollution, damage to public health, wildlife and habitat loss, water use, land use, and global warming emissions.