Final answer:
The correct way to express 1/2 cc is 1/2 milliliter since one cubic centimeter is equal to one milliliter, and both are interchangeable in the SI metric system.
Step-by-step explanation:
The proper way to express 1/2 cc is 1/2 milliliter. This is because one cubic centimeter (cm³) is the volume of a cube with each side measuring exactly one centimeter, which is also equivalent to one milliliter (mL). Since the metric system is based on units that scale with multiples of ten, the volume units within this system are consistent and convertible. For instance, 1,000 cubic centimeters make up one liter, and since a milliliter is 1/1,000th of a liter, a milliliter is equal to one cubic centimeter. Therefore, 1/2 cc can also be expressed as 1/2 mL, demonstrating the interchangeability of these two units in the International System of Units (SI).