What prevents a white dwarf from completely collapsing upon itself?

Fusion

Explanation:

What keeps the white dwarf "alive" is fusion reactions in its core. When the fusion stops, it has no energy -- therefore it cannot support itself.

Hope that helped!

Also, you should read about Chandrasekhar limit!

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a

the correct answer is b