What are the primary gases that make up the Earth's atmosphere?

The correct answer identifies the primary gases that constitute approximately 99% of the Earth's atmosphere. Nitrogen makes up about 78% of the atmosphere, which is crucial as it provides stability and does not react easily with other elements. Oxygen, accounting for around 21%, is essential for respiration in most living organisms and plays a vital role in combustion processes. Argon, although it constitutes a smaller portion at approximately 0.93%, is the third most abundant gas and is inert, contributing to the atmospheric composition without actively engaging in chemical reactions that affect life or temperature.

The other options do not accurately reflect the current understanding of atmospheric composition. For instance, the first option introduces carbon dioxide at a much lower percentage, which is accurate but doesn't include argon. The third option's values misrepresent the percentages of oxygen, nitrogen, and carbon dioxide, leading to a total that doesn’t align with the actual atmospheric composition. The fourth option misplaces the percentages of nitrogen, oxygen, and argon, leading to a false representation of our atmosphere.