Which of the following human activities would affect the natural cycles on earth? a. burning fossil fuels c. factories giving off pollutants via smokestacks b. growth of agriculture d. all of the above

D. All of the above

Explanation: Human activities such as deforestation, industrialization, fossil fuel burning have direct and indirect effect in the biochemical, geographical and physical processes that affects the earth.

Digging up fossil fuels and burning them, leads to the release of carbon dioxide in the atmosphere faster than natural systems can clean up, increase in the release of carbon dioxide leads to an increase in greenhouse gases in the atmosphere which causes the global warming.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.