How scientists can have multiple theories about the effects of global warming.?

Answer and Explaination:

The global climate is very complex. There are several different factors to consider such as temperature, precipitation, humidity, and overall climate. All of these theories are based on predictions. It is hard to predict what will happen in one region and how that will affect other regions on a global scale. Nobody knows with 100% certainty what will happen.

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b. the carbon cycle ensures living things have a source of hydrogen