Question

What was the composition of Earth's early atmosphere before the ozone layer formed?

Options

• Nitrogen, oxygen, and carbon dioxide

• Water vapour, methane, carbon dioxide, and ammonia

• Primarily oxygen and nitrogen

• Only hydrogen and helium

Answer 1

Water vapour, methane, carbon dioxide, and ammonia were released from the molten mass and covered Earth's surface. Ultraviolet rays broke water into hydrogen and oxygen; lighter hydrogen escaped, while oxygen combined with ammonia and methane to form water, carbon dioxide, and other substances. The ozone layer formed later as atmospheric conditions changed.