Task: Instance Description Understanding (ontology: Sciences/Computer_Science)

Which of the following definitions best describes the instance 'picomole'?

A. A pathologic primary tumor stage for ovary according to AJCC 7th edition indicating that the tumor is limited to the ovaries (one or both).
B. A substance unit equal to a millionth of a mol or 10^[-6] mol.
C. A substance unit equal to 10^[-12] mol.
D. A substance unit equal to one thousandth of one millionth of a mole or 10^[-9] mol.

Answer: A substance unit equal to 10^[-12] mol.