Yes. The road bikes and MTBs have multiple gears while the BMX and track bikes only have one.
Initially, bike gears were inside the rear hub. There's records of internal hub gears being patented as early as the 1880's. The first successful implementation was William Reilly's "The Hub", a 2-speed internal gear hub, which went into production in England in 1898.
Yes. The road bikes and MTBs have multiple gears while the BMX and track bikes only have one.
yes
MotoGP bikes have 6 gears.
Depending on the bike yes most adult sized bikes have gears
They make cars and bikes work.
Unfortunately, you can't change gears on bikes in HeartGold.
dirt bikes in the past had less gears and power then dirt bikes have today
Yes in fact i have one they have three gears and neutral but most are automatic
There are internally geared bikes, where all the gears are tucked away inside the hub and then there are externally geared bikes, with a stack of differently sized sprockets on the outside of the hub. Apart from that they're just called gears.
Racing bikes are so different from your conventional bike in many ways. They are made to be a lot lighter than the average bike you see today and are made for speed. Racing bikes are fitted with minimum components the gears can range from 18 gears to 30 gears.
Not all bikes have "gear". Straddle bikes and direct drive bikes - with cranks directly attached to a wheel axle - don't have gears.
I recommend it. If you do not shift gears while riding a dirtbike, the motor can overheat and blow up.