Explain how white dwarf stars can be both hot and dim.

It's because of their small size.The white dwarf stars only have volume around the same size as of earth. So, that's why white dwarf stars can be both hot and dim.

Hope it helps!

in most common fires, oxygen is needed for an oxidation reaction to takes place. the combination of oxygen with any element as fuel can create fire and combustion will occur especially if wood, light materials and other combustible things are combine with oxygen.