Square metres for area, metres for linear dimensions.
A metre.
The most appropriate metric unit to measure the mass of a concrete block is kilograms (kg).
The appropriate metric unit to measure the mass of a lawn mower would be kilograms (kg). This unit is commonly used for measuring the weight of objects in metric system.
Metric
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.
The most appropriate measure is a metre.
A gram would be an appropriate measure for its mass.
A litre.
By unit of length and distance and conversion ,we can say that the most appropriate unit to measure the length of a finger is cm.
An appropriate metric unit of mass for a pencil would be grams.
The metric unit used to measure the mass of a pencil would be grams (g).
The metric unit of length is the 'meter'.