Final answer:
The top four gases making up Earth's atmosphere in descending order of abundance are Nitrogen, Oxygen, Argon, and Carbon Dioxide, matching option A.
Step-by-step explanation:
The correct answer to the question about the four most abundant gases in Earth's atmosphere and their relative abundances is: Nitrogen, Oxygen, Argon, and Carbon dioxide, in descending order of abundance. This corresponds to option A. The Earth's atmosphere is a complex system, and its composition is crucial for supporting life. The atmosphere is composed primarily of Nitrogen (78%) which acts as a diluting agent for oxygen and is essential for making proteins, although in its gaseous form it's generally unavailable to most living things. Oxygen, the second most abundant gas, accounts for about 21% of the atmosphere and is necessary for aerobic respiration and combustion. Argon, a noble gas, is the third most prevalent gas at approximately 0.9%, used in applications such as welding and light bulbs due to its inert characteristics. Finally, Carbon Dioxide (0.03%) is a minor yet critical component that helps control the Earth's temperature.