The oxygen in the blood enters the circulatory system and is used by the cells in the body.

As a result the box will start to leak and water and oxygen can then enter the box.

If oxygen can enter, the wood might catch fire, and the production would be ruined.

Therefore, oxygen leaves the alveolus and enters the red blood cells.

When the mechanic opened the manhole more oxygen entered and the explosion took place.

After cooling the engine walls, the compressed oxygen entered the top end of the chamber in a swirling pattern.

Once the oxygen has entered the bloodstream it must be transported to working muscle and waste products removed.

Any oxygen present in the con- tainer will be used up and no more can enter.

Some oxygen enters the water through mechanical mixing with air, though that is probably not very significant in most salt marshes.

Already the atmosphere was beginning to be tainted, as it always becomes in a closed place when no fresh oxygen can enter.