It depends on what characteristic you want to measure! Its mass, its height, the amount of body fat, the fineness of its fleece?
jolts or something
inches
Kilograms.
mililiters
Millimetre.
What is the mass of 1 sheep?
Feet.
a centimeter
A shoe.
You would use CM or INCHES to measure a knife
what unit of measure is thickness og a ballpen
Ounces or milliliters.
A kilometre.
Kilometers
meters
inches
Square footage.