Choose the correct verb to agree in number with the subject of the following sentence.
Each of these salad dressings __________ low in calories.?

Match the following binary devices with their two states:

I. laser diode II. telephone circuit III. microprocessor IV. transistor V. digital video disc A. circuits on or circuits off B. voltage on or voltage off C. connected or not connected D. reflect or disperse laser beam E. presence and absence of light

PDF stands for _____.

A. Portable Document Format B. Published Data Format C. Photographic Data File D. Paired Database File