Liters, milliliters.
The metric unit used most often to measure liquids is the liter (L). It is a unit of capacity and is commonly used in everyday life and in the scientific community.
Milliliter
The basic unit of length in the metric system is the meter. Grams are used to measure weight and liter is used to measure liquid capacity.
The liter (or litre) will commonly be used for that.
The metric unit of length is the 'meter'.
The metric unit used to measure weight is the kilogram (kg).
Any metric measure of volume.
Example:4 Meters squared, 5 kiloliters. Any metric length unit squared. All metric units with the suffix "liter"
The Newton
The metric unit is the meter scaled to centimeters.
The metric unit used to measure a picnic cooler would be liters (L) for volume.
I assume you mean volume rather than capacity. The milliliter would be the best answer. It is 1 thousandth of a liter.