The most abundant materials in the solar nebula were which gases?

• A. Oxygen and nitrogen
• B. Neon and argon
• C. Water and methane
• D. Hydrogen and helium gases

Answer: (D)

In the early solar system, the gas cloud (the solar nebula) was dominated by hydrogen and helium because these are the lightest and most abundant elements produced in the Big Bang. They account for the vast majority of the nebula’s mass, with hydrogen making up the largest portion and helium the second. Heavier elements and compounds—like water, methane, and other molecules formed later in stars—exist in much smaller amounts relative to the bulk hydrogen and helium. Noble gases such as neon and argon are present too, but far less abundant than hydrogen and helium. So the most abundant materials were hydrogen and helium gases.