Answer:
In stars, the intense pressures and temperatures are provided by gravity. A star has such large mass that the gravity created by this mass crushes the star inward enough to ignite nuclear fusion
Explanation:
The sun does not run out of oxygen for the simple fact that it does not use oxygen to burn. The burning of the sun is not chemical combustion. It is nuclear fusion. Don't think of the sun as a giant campfire. It is more like a giant hydrogen bomb.
- https://www.wtamu.edu/~cbaird/sq/2015/03/20/why-does-the-sun-not-run-out-of-oxygen-as-it-burns/#:~:text=In%20stars%2C%20the%20intense%20pressures,enough%20to%20ignite%20nuclear%20fusion.
