Need answer asap which statement about the earth’s atmosphere is true

in the past few decades, carbon dioxide levels have been rising.

a recent decrease in carbon dioxide levels will increase plant growth on earth.

in the past few decades, carbon dioxide levels have been falling.

a recent increase in carbon dioxide levels can contribute to a long-term cooling of earth’s climate.

In the past few decades, Carbon dioxide levels has been rising.

Explanation:

Rising levels of Carbon dioxide has become an immediate concern for the Environmentalists.This is because carbon dioxide is a green house gas and risen levels of green house gases can lead to unusual warming up of the Earth's Atmosphere.This phenomenon is termed as Global warming.Global warming can lead to seasonal variation and melting of the ice caps to flood several continents.In Last few decades The levels of Carbon dioxide is rising at an alarming rate.This rise occurs due to the to burning of fossil fuels, combustion of fuels in automobiles, Deforestation etcAn immediate step is needed to check this addition of carbon dioxide.

The correct answer:   [c]:   "cell phone call" .