A question for mountain road bike?

Question

what parts of body does it work on the most if you do it alot?
From the two types.

Answer 1

Primarily it is lower body. So legs, obviously as well as stomach. Thighs get a good work out. Primarily, cycling is a cardio vascular work out. So as well as developing strong legs, its very good for the heart and lungs.

P.S. Whats a mountian road bike? Is that a hybid?