How many different typefaces should you use in business documents?
three
as many as possible to keep it interesting
the number you need to organize your information
the same amount as the number of paragraphs in the document

Answer an editor;

Combining the emissions released by fossil fuel burning and  the carbon released via land use change, we get a total of 8.7 gt. since the problem states that the oceans "take up" or sequester  2.4 gt carbon  per year, we subtract that value from 8.7 gt, leaving us with 6.3 gt of carbon. since the problem states that 3.4 gt carbon dioxide emissions end up in the atmosphere, the "missing sink" of carbon takes up 2.9 gt, a value we got by subtracting the 3.4 gt amount recorded from the 6.3 gt carbon left available after the oceans sequester the carbon dioxide. 

Hey there! they are all mostly focused on construction and such as building.hope this and have a great day (: