Answer 1

Promises are a much cleaner way to implement callbacks.
Promises are essentially built on top of callbacks with syntactic sugar to make it much more readable. Otherwise, what often results with callbacks is a series of multilevel nested functions.
I've provided some additional links with more in-depth detail:
- https://stackoverflow.com/questions/22539815/arent-promises-just-callbacks
- https://softwareengineering.stackexchange.com/questions/302455/is-there-really-a-fundamental-difference-between-callbacks-and-promises