The defining constants for the International System of Units (SI) used in physics are set, with no uncertainty. Other physical constants which cannot be predicted but determine the nature of the physical world are measured. Match the SI defining constant with its units. - Speed of light (c) - Planck's constant (h) - Charge on the electron (e) - Boltzmann constant (k) - Avagadro constant (NA ) A. m/s B. J s C. mol-1 D. J K-1 E. C