What is the main composition of Jupiter's atmosphere?

Jupiter's atmosphere is primarily composed of hydrogen and helium, making it the largest planet in the solar system, with these elements constituting about 90% of its atmosphere. This composition reflects the planet's formation and the primordial ingredients of the solar nebula, from which the solar system formed.

Hydrogen, being the lightest and most abundant element in the universe, dominates Jupiter's gaseous envelope, while helium, the second most abundant element, is present in significant amounts as well. Together, these two substances create a thick, swirling atmosphere with varied cloud bands and turbulent weather systems, including the famous Great Red Spot.

In contrast, the other options consist of gases or compounds that are found in smaller quantities in Jupiter's atmosphere. For instance, while methane and ammonia do exist in trace amounts, they do not constitute the main components. Similarly, oxygen, nitrogen, carbon monoxide, and water are also present in the atmosphere but are overshadowed by the overwhelming presence of hydrogen and helium.