Metres or square metres - depending on whether you wanted to measure its linear dimensions or its floor-space (area).
The width of a pin would typically be measured in millimeters (mm).
Metres, to measure its length or width, square metres to measure its area.
The metric unit used for measuring the width of a fingernail is usually millimeters (mm).
A common house fly is a very small animal. In order to get an accurate measurement, you would have to use millimeters.
Please specify what you want to measure about the bucket, for example its height, width, circumference, volume, color, albedo, etc.
I would go with millimetres
cm
It would be millimetres.
centimetre
Kilometres
The width of a pin would typically be measured in millimeters (mm).
Metres, to measure its length or width, square metres to measure its area.
The metric unit used for measuring the width of a fingernail is usually millimeters (mm).
a yard stick
meters
A common house fly is a very small animal. In order to get an accurate measurement, you would have to use millimeters.
The metric unit of the meter would be the appropriate measure of the area of classroom. Calculating area involves multiplying the length (in meters) of the classroom's length and width. Area of the classroom would be in square (^2) meters.