Lunar oxygen isotopic ratios are essentially identical to Earth, with no evidence of a contribution from another solar body.

The oxygen isotonic ratios of the coral tell us the water temperature at the time the coral was growing.

There's enough to breathe, but a higher oxygen ratio will be more comfortable for humans.

Her air pressure was lower than ours but her oxygen ratio was higher; we could breathe it.

Class - two or more groups that have a similar chemistry and oxygen isotope ratios.

An example of a niche use is as an anesthetic agent (in an 85% ethylene/15% oxygen ratio).

Teeth are not subject to continual remodelling and so their isotopic oxygen ratios remain constant from the time of formation.

The isotopic oxygen ratios, then, of teeth represent the ratios of the region in which the individual was born and raised.

If so, the data about oxygen isotope ratios would be incomplete, especially for times when the extremities were coolest.

"You can increase the oxygen ratio if necessary," Vosnesensky said.