a) A type of data compression where a string of identical values is replaced by codes to indicate the value and the number of times it occurs. Thus, a string of 70 spaces can be replaced by two bytes. One to indicate the string consists of spaces and a byte to indicate there are 70 of them. Run-Length Coding is not as efficient as DCT for compression of pictures or video, since long sequences of the same values rarely exist in images. Run-Length Coding is part of JPEG, MPEG, H.261, and H.263 compression schemes. b) A coding scheme that counts the number of similar bits instead of sending them individually. c) Coding of data with different numbers of bits. Frequently reoccurring data has the smallest number of bits, data seldom reoccurring have the highest number of bits.