Which of the following instruments is used to measure very small volumes?

The micropipet is specifically designed for measuring and transferring very small volumes of liquid, typically in the range of microliters (µL). This makes it an essential tool in molecular biology, biochemistry, and various laboratory settings where precision is crucial, such as during DNA sequencing or other assays that require accurate small-volume liquid handling.

Graduated cylinders, while useful for measuring liquids, are generally designed for larger volumes and do not provide the level of precision needed for very small measurements. Hot plates are used for heating substances, and laboratory balances are used to measure mass rather than volume. Therefore, the micropipet is the most appropriate instrument for measuring very small volumes accurately.