____ shift keying represents 0s and 1s by different changes in the phase of a waveform.?

The identifiers in an enumeration ________.

a. must be unique. b. may be duplicated. c. must be lowercase letters and cannot contain numbers. d. must be uppercase letters and cannot contain numbers.

If you have not done so already, visit some Web site that offers tours of 3D virtual worlds. Record your experiences. Discuss

a. Length of time to download and install the player b. The process of learning to navigate the world c. Download times for the virtual worlds.