Along with Oxygen, which element is primarily responsible for the sky appearing blue?

Nitrogen is primarily responsible for the sky appearing blue because of a phenomenon called Rayleigh scattering. In the Earth's atmosphere, the blue light from the sun is scattered more than other colors due to its shorter wavelength. As sunlight passes through the atmosphere, the nitrogen molecules scatter the blue light in all directions, making the sky appear blue to our eyes. This scattering effect is also influenced by the abundance of nitrogen in the atmosphere, making it the primary element responsible for the blue appearance of the sky.