AUDIO DEVICES: Difference between different audio devices and sound editing

I am here to ask some technical questions about differences between some audio devices and about them point by point. I am a beginner or noob in audio devices and sound editing.
Please answer this question point by point.

Questions:

1. How a bass boosted or different types of headphones are made? Is there hardware difference or software difference between flat headphones and bass headphones?
2. Can you produce flat sound from a bass headphone by using some software or not? (for purpose of professional audio editing)
3. Can you make changes to a bass boosted headphones manually (to hardware or its software) to be able to use it as flat headphones for audio editing? If yes, then how?
4. Why professionals do not use earphones for audio editing? And can we use it for professional sound editing? (because I think that some earphones produce flat or pure sound)
5. Can we do audio editing using some speakers? and why?