I presume you mean driving a car, and you put your foot down to 'go harder'. :)
It means its harder
No
I don't know what you mean by harder snakes. Most snakes eat mice.
Harder, tighter, less floppy.
it means push harder
it means T (research harder)
If you mean harder as in muscles, protein and complex carbohydrates usually help build muscle but exercise is the most important. If you mean harder as in an erect penis, there is no food that will help that. General good health is the only thing that can aid in an erection.
to go harder
Rub harder when you clean.
mmm I guess you mean Portuguese not Brazilian. And yeah, portuguese is a little bit harder to pronounce than spanish.
It means that you need to work much harder.