Complex sentence: The M56 Scorpion was an American military armoured vehicle that was a relatively light-weight self-propelled anti-tank gun, which featured a 90mm M54 gun with a simple gun shield, and unprotected crew compartment.
Split into simpler sentences: The M56 Scorpion was an American military armoured vehicle. It was a relatively light-weight self-propelled anti-tank gun, which featured a 90mm M54 gun with a simple gun shield, and unprotected crew compartment.