The most appropriate metric unit to measure the mass of a concrete block is kilograms (kg).
millometers
The appropriate SI base unit to measure the time it takes to play a CD is the second (s).
Kilograms or pounds.
An appropriate metric unit to measure the Mississippi River would be kilometers (km) as it provides a more accurate representation of the river's length.
Meters
The standard unit to measure mass is kilograms.
appropriate unit to measure the width of a textbook = ce ntimeters
The appropriate unit is a metre.
Meters
A centimetre.
yards
Hs
feet
miles
The most appropriate metric unit to measure the mass of a concrete block is kilograms (kg).
The appropriate unit to measure weight is the newton. Now, if it is really the mass you wanted, you could use kilogram or gram.