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.
Amy tanks do NOT have chained wheels. Tanks are tread laying machines.
caterpillar tracks have large surface area than wheels. larger the surface area, smaller will be the pressure. Hence tanks and buldozers are fitted with caterpillar tracks
They're called threads, and they are used because they work where wheels would bog down (like mud and sand).
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.
They're heavily armoured and they have a cannon. Also their caterpillar wheels help when going over uneven ground.
The added surface area allows for more traction and less sinking of the vehicle when in mud or sand.
Battle tanks use tracks to spread their weight on soft ground. Tanks weigh 40+ tons; If they used wheels they would often get stuck. It's the same reason earth moving equipment (bulldozers) use tracks.
Pretty much the way tanks work today. A gasoline (or diesel) engine turns the drive sprocket, which pulls on the track. Road wheels roll on the inside of the track. The earliest tanks did not have a turret for a main gun like today's tanks, but had gun mounts (sponsons) on the sides. There was no Power Steering, speed was slow, they were noisy, hot, and broke down a lot.
Tracks have more traction because they cover more ground with no spaces in between. Wheeled vehicles have spaces between the wheels which allow the wheels to fall into holes/cracks/crevices/etc; allowing the wheeled vehicle to get stuck.
Caterpillar tracks are knobbly strips of metal or rubber, which wrap around the wheels of tanks, bulldozers and other off road vehicles. They stop the wheels from getting stuck in muddy or sandy ground. This is a very helpful technique.
Many items have capacity that are common everyday items such as: a cup, a football, a carbonator, bike wheels, gas tanks, etc. There are different types of capacity such as: air capacity (wheels), liquid capacity (a cup or a gas tank), etc.
Originally to break through enemy lines, since they were bullet proof and hand-grenade proof; and had tracks instead of wheels to traverse through mud with.