kilometers
a millimetre
Miles is best.
Kilometer or mile
They are meters to measure
Kilometres
To measure the distance across your yard, you would typically use meters as the metric unit. If the yard is relatively small, you might also use centimeters for more precise measurements. For larger areas, kilometers could be applicable, but for most residential yards, meters would be the most appropriate choice.
The answer depends on the context in which the word "state" is used. If you mean the state of matter, there is no difference between the metric and the ancient system. In either system a gas is a gas gas gas (as JJF might say)!If by state, you mean a geopolitical region, the answer will then depend on what characteristic of the state you wish to measure: most economic measures would not be metric. Mean altitude would be measured in metres (above mean sea level), are on square kilometres, and so on.
You would use the metric unit "liters" to measure the capacity of a hot water tank.
You would use kilograms (kg) to measure someone's mass in metric units.
You would typically use the metric unit of centimeters to measure the growth of your hair.
Metres
You would use liters (L) to measure the volume of a soda container in the metric system.