Earth's atmosphere mostly consists of which two gases?
nitrogen and oxygen
carbon dioxide and oxygen
nitrogen and carbon dioxide
hydrogen and helium
100 exam-style questions on CIE IGCSE Physics 6.1 The Earth and the Solar System, covering 6.1.1a Rotation of the Earth, the seasons and the Moon, 6.1.1b Average orbital speed, 6.1.2a Contents of the Solar System, 6.1.2b Formation of the Solar System, 6.1.2c Gravitational field strength of a planet, and 6.1.2d Orbits and gravitational attraction. Each one has a worked solution and a mark scheme showing where the marks go.