1.   Near the top of the mountain, the climbers relied on bottled oxygen to breathe.

2.   Even now, she and her mother are virtual prisoners in their home, because Jade depends on bottled oxygen.

3.   He climbs mountains the old-fashioned way, without the help of bottled oxygen.

4.   The Russian team would then enter with bottled oxygen and breathing equipment.

5.   To do that, he knew he must first beat Lewis, which he is pretty well convinced is not akin to climbing Mount Everest without bottled oxygen.

6.   All were climbing without bottled oxygen, used by most mountaineers for energy and to avoid hallucinations.

7.   He will not use bottled oxygen.

8.   Like many other climbers, he will use bottled oxygen to supplement his breathing at the highest altitudes.

9.   Like most Nepalese Sherpas, Chhiri climbed without using bottled oxygen, where air pressure is so low that breathing is strenuous.

10.   Like most Nepalese Sherpas, Chhiri climbs without bottled oxygen, even though air pressure is low, making breathing strenuous.