The composition of the atmosphere has changed over time ... Respiration is the chemical process that occurs inside cells to release energy from glucose when it reacts with oxygen.

The study also provides a new approach to solving one of the biggest enduring scientific mysteries: when did plate tectonics begin?

Occasionally volcanic eruptions result in huge amounts of primary and secondary aerosols both at the ground and in the stratosphere (Boulon et al. 2011). The size and chemical composition of the ...