Well, a track bike is a bike dedicated for use on a velodrome. It has a fixed gear, no brakes, often a steel drop bar and some other features.
But with a but of determination you can stick a fixed gear rear wheel in any kind of bike. The wouldn't make it a track bike, but would make it a fixie.
If you want to be hard core in your fixie riding, the "purest" is of course to ride a track bike in traffic too.
it would all depend on what gearing ratios were used , there is a difference between long track bikes and short track bikes ,on average they can reach speeds of around 70 miles per hour .
motor cross is faster
I have no idea what you mean by "gear bike", so the question can't be answered.
Mountain bike helmets are better than dirt bike helmets
The difference is the person who is possessing. For example you would say "I have a bike" or "He has a bike". You would not, however, say "I has a bike" or "He have a bike" unless you're ignorant and uneducated.
there is not much difference usually people think that they are smaller and are more powerful, which is true, although they can be normally sized
difference between 220cc and 150cc is that 150cc has less cc than 200cc
bike
The difference is that the mountain bike tube is much burlier and wider than the dirt jump tube but may not be as strong in terms of hard hitting strength.
The length, and depending on horsepower, it could be larger for the higher horsepower bike.
A rocket is cooler:)
no not necessarily