Question

earths atmosphere is a layer of gases that surrounds our planet. what gas makes up the largest percentage of the atmosphere?
nitrogen, making up about 78% of the atmosphere
carbon dioxide, important for plants but too much can be harmful
oxygen, essential for animal life and emitted by plants
water vapor, present in varying amounts and forming clouds

Explanation:

Nitrogen is the most abundant gas in Earth's atmosphere, constituting approximately 78% by volume. Other gases like carbon - dioxide, oxygen, and water vapor are present in smaller percentages.

Answer:

nitrogen, making up about 78% of the atmosphere