The most gears you can have straight off the shop floor is 33, but dependent on how much rebuilding and custom fabrication you're willing to do there's really no upper limit. Keep in mind that the actual number of usefully different gear ratio is usually considerably less than the number of gears.
All depends on the bike. The most you can currently have on a stock bike would be 33, but for someone with a taste for customization that can easily be increased. Most MTBs and hybrids will havebetween 21-27, most road bikes 18-22. Thing is that although you might have 30 or so different combos you don't really have 30 different gear ratios. Something like 1/3 of the ratios will repeat themselves as you work your way through the gears.
2 gears
MotoGP bikes have 6 gears.
depends on the model. from 2-7 gears
It depends on the bike if the engine of bike is heavy it has more gears. Usually 5 gears are max gears.
4 to 6
only one
Depending on the mountain bike that you have will depict the amount of gears. Most bikes for adults typically have about 21 gears. If this does no answer your question then what are levels?
there are 6 gears, like any other race bike
This bike has a six speed gear box, so six gears.
4
6
well from my experience "if understand the question correctly" take the number of gears on the back derailleur and multiply that number with how many gears are on the front derailleur