Charles Keeling’s work at the National Oceanic and Atmospheric Administration (NOAA) Mauna Loa Observatory paved the way to understanding how human activities can lead to global warming.
Which greenhouse gas did Charles Keeling measure at the observatory?
A)
carbon monoxide
B)
methane
C)
nitrous oxide
D)
carbon dioxide

c is the correct answer hope this !

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evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.