Which two components make up the greatest percentage of the atmosphere?

Earth Atmosphere:

The earth atmosphere is composed of a number of gases or elements, as they are required to sustain the environment and air present in the atmosphere. As there are various portions of the air mixture, and most of the elements are present are in high level or number of molecules are in more denser form.

Explanation:

Nitrogen, N: In our atmosphere we have nitrogen as the most abundant element inside a sample of air, as the air contains about 78% of the nitrogen molecules in total. As it has great importance to the atmosphere and the whole ecosystem that we live inside.Oxygen,O₂: Oxygen can be termed as the most important and vital element for the living beings, and most of the materials to exists. As living beings require more  oxygen for driving the cellular respiration and other cellular functions. As they form the basic mechanism for driving the life force by being the main cause of the photosynthesis which involves the production of the energy and NADH.