Final answer:
In aviation, the MAIN FUEL tapes display fuel levels from 0-1200 lbs, with a caution line commonly marked at 200 lbs to indicate a low fuel state and prompt necessary actions.
Step-by-step explanation:
The MAIN FUEL tapes range from 0-1200 lbs and are typically used in aviation to indicate the amount of fuel in an aircraft's tanks. These tapes usually include a marked low fuel caution line to alert pilots when the fuel is reaching a critically low level. This line can vary by aircraft, but for instructional purposes, let's say the caution line is marked at 200 lbs. When the fuel quantity approaches this mark, it serves as a visual reminder to the flight crew that they are nearing a minimum fuel state where they will need to consider landing or refueling options.