Centimeters or inches
To measure a leaf? A Ruler with a Centimeter measurement on it. Or if your like me and the distance from you knuckle to your thumb is 1in, use that ^-^
always the meter to measure length. This is an SI (international) unit of measurment, and is the standard international unit of measurment for length.
Centimeters
A kilometre.
Cm .
meeters?
Centimeters
Time
a millimeter
Millimetre.
You can use a ruler or a tape measure to measure the length of a test tube. Simply place the test tube on a flat surface and align the ruler or tape measure along its length to get an accurate measurement.
Milligrams