Question

The property that distinguishes the thermosphere most is the presence of

Answer 1

B. Ozone. It's Ozone because thermo in the word thermosphere means heat. The word sphere means the shape, which is the shape of Earth, and you're asking for the most of the presence, which only means in earth, that's why I pick B.

Answer 2

The property that distinguishes the thermosphere most is the presence of C. Heat