Anthropology and sociology
Answer:
multicellular; single celled organisms are often too tiny to be seen without a microscope
Answer:
Acid rain is caused by emissions of sulphur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids.
Biodiversity increases as the number of populations grow, because a greater population generally means a more diverse one.
However, this is not always true, so I'm not sure what answer they're looking for.
Carbon can bond up to 4 times so it can be stronger in some cases than other elements.
