mostly from age or over use.
friction
That happned on our 1973 Camarro, it was due to some lose wires, this can also happen is the equipment is old.
some have 5 gears and some have 6 gears i have a 1999 and mine has 5
Either the transmission needs an oil and filter change/ additive to it(some mixture they sell at walmart to prevent sticking gears). Or the transmission is going bad. might need a new one
there is a slight way if you have a good enough engine and some skill its called power shifting you should google it
Strokes can cause this because they make a person lose some of their brain function. Brain damage can also cause this.
it could be the battery or altinator
Smash it on the ground until it is in pieces, then there should be some gears out.
Gears on bicycles do the same thing as gears do wherever they're found, they allow you to trade power for speed, or the other way around. This is very useful if your riding conditions (up/downhill, head/tailwind, Carrying/empty) change frequently. OTOH, being able to use gears means your bike needs some extra parts and some extra care. If your riding conditions don't change much, then it MIGHT be worth sticking to a single-speed bike. You lose a little usefulness, but the bike becomes a little more robust.
no. Unless it is an older car as some used electronic modelling to inrease efficency say 1980-1985.
Yes some came stock with 3.55 gears
there are gears