The approximate percentage of nitrogen in Earth’s atmosphere is:

The correct option is 78%.

Step-by-step Explanation:

Earth’s atmosphere is a layer of gases surrounding the planet, held in place by gravity. It is composed of a mixture of several different gases in varying proportions.

The major gaseous components of dry air in the Earth's lower atmosphere by volume are approximately:

1. Nitrogen ($N_2$): ~78% (or about 78.08%)
2. Oxygen ($O_2$): ~21% (or about 20.95%)
3. Argon ($\mathrm{Ar}$): ~0.93%
4. Carbon Dioxide (${\mathrm{CO}}_2$): ~0.04%
5. Trace amounts of other gases such as neon, helium, methane, krypton, and hydrogen.

Therefore, nitrogen is by far the most abundant gas in Earth's atmosphere, making up approximately 78% of its total volume.