Which of the following explains how scientists know that current global warming is related to human activities? Atmospheric carbon has increased much faster than in the past.
There were no greenhouse gases in the atmosphere in the past.
There was more methane in the atmosphere 6,000 years ago.
There is more water vapor in the atmosphere today than the past.

This is a typical grassland food web. it is also a small picture of an important cycle on earth: the carbon cycle. describe how the carbon gets into this food web. a) bacteria and fungi, the decomposers, recycle carbon from dead organisms. b) carbon is found in the grass and is passed from one level to the next in this food web. eliminate c) all living things give off carbon dioxide as a by-product of respiration and it is released into the atmosphere. d) plants use carbon dioxide as a reactant in photosynthesis, to make usable chemical energy in the form of a sugar.