Oh, dude, like, the unit you'd use for the length of the snake would be, um, meters or feet or, like, inches. I mean, unless you're measuring a really tiny snake, then maybe centimeters. But hey, as long as you're not trying to measure it in bananas or something, you should be good to go.
a meter?
meters
I would use centimeters.
miles edit: kilometers in the rest of the world
Any metric unit would do. But it might be easier to pick something smaller than the length of the pencil, like a centimeter, or a millimeter.
The ISO length unit to use would be the cementer.
It's SI unit is meters
I would use centimetres.
I would use inches.
A meter.
The length of an aeroplane would be measured in metres.
miles or kilomiters
You would use the SI unit meter (m) to measure the length of a DVD case.
It would be normal to use either meters or feet, but you can use any unit for length (inches, cm, mm, km, etc.)
i would use inches
You would use meters.
I would use feet