They're called threads,
and they are used because they work where wheels would bog down (like mud and sand).
You may be seeing the tread as "long chain" . The treads are wrapped around wheels to spread the weight more evenly. Because of their steel construction they are less susceptible to small arms fire.
Amy tanks do NOT have chained wheels. Tanks are tread laying machines.
Tanks have interior wheels that drive their treads, which revolve around the outside of the entire set of hub wheels. Light tanks may have road wheels that are fitted underneath, to avoid damaging the surfaces of roadways and bridges.
The machinegun and barbed wire were causing a stale-mate in WWI; tanks (being bullet proof and having tracks instead of wheels) were able to break that stale-mate.
Yes!
One can find information on military tanks from encyclopedias, both online and off, as well as books focused on the military. Online websites that offer interesting information on tanks include Military Factory and Military-Today.
The military arrived with their tanks and guns.
Tanks
There are many websites that are dedicated to the history of tanks. The Military Channel from Discovery is one of the most prominent resources of the history of military tanks. There are also encyclopedias and books available for purchase from Amazon.
Wood.
Kay Jackson has written: 'Military tanks in action' -- subject(s): Juvenile literature, Tanks (Military science)
They invented military tanks mainly to make advances where the machine gun fire was too heavy for unprotected soldiers to advance on foot.