12
Steel
Magnesium is used for.......STUFF
by casteing together of iron and steel
car bodies are made of steel alloy that contains iron and carbon.
so they don`t get damaged as easily
Too expensive
It depends on the car, but for most cars the frame and body is made of steel and is therefore ferrous. However, some newer hybrid car bodies are made of aluminum or plastic and therefore not ferrous.
Oxydation of magnesium: 2 Mg + O2 = 2 MgO
Because of the cost
By normal car bodies, i am guessing you mean real car bodies. There is Test Drive and Midnight Club.
The bodies of most cars in 1920 were made of Tin or Steel. The Ford Model T was known as the Tin Lizzie for this reason.