A may be formed from many related hypotheses that have been tested and support the evidence.

A theory   may be formed from many related hypotheses that have been tested and support the evidence.

Explanation:

A THEORY -: A theory is a well-established, tested explanation that gives some part of the natural world a unified description. A hypothesis is focused on substantiated knowledge, repeated testing, and a large community of scientists / researchers agree on it.

The aim of a theory is to try to understand phenomena that many researchers have examined extensively and carefully over time. A hypothesis does not prove that the "unified description is correct." However, because the theory is the result of scientifically based research, the theory (as opposed to a single hypothesis) is more likely to be correct. Any hypothesis can (and should) be tested, but many trained scientists must scientifically perform and study the experiments.

Explanation:

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."