Greenhouse Effect

The question is poorly phrased. The most predominant gas in the atmosphere is Nitrogen (78%), followed by Oxygen (21%) and Argon (0.9%). All the options provided are trace gases.

Carbon dioxide ( ): 420 ppm (0.042%)
Carbon monoxide (CO): Variable, around 0.1 ppm
Propane ( ) and Butane ( ): Extremely low, sub-ppb levels.
Of the choices given, Carbon dioxide is the most abundant.

Let's analyze each statement:

(A) is correct. The natural greenhouse effect keeps the Earth's average temperature at about 15°C, making it habitable. Without it, the average temperature would be about -18°C.
(B) is correct. Greenhouse gases like carbon dioxide and methane are emitted through natural processes like respiration, volcanic eruptions, and decomposition.
(C) is correct. This is the definition of the greenhouse effect's function.
(D) is correct. The scientific consensus is that the increased concentration of greenhouse gases due to human activities is the primary driver of current global warming.
All the provided statements are factually correct. There seems to be an error in the question as it asks for an incorrect statement.