Earth's atmosphere has the lowest concentration of which of the following gases?
a. oxygen
b. nitrogen
c. carbon dioxide
d. argon

The correct answer is C - carbon dioxide.

The distribution of gases in the earth's atmosphere is as follows:

1. Nitrogen - 78  %

2. Oxygen - 21 %

3. Argon - 0.93 %

4. Carbon dioxide - 0.038%

Nitrogen, oxygen and argon are permanent gases whose percentage in  the atmosphere does not change from day to day.

Gases such as carbon dioxide, nitrous oxides, methane, and ozone are known as trace gases which make up 0.1% of the atmosphere.

the answer to your question is slate

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."