On all of Answers.com, ReferenceAnswers might win, since an entire encyclopedia or collection of books might be added to the site in a very short period of time... much faster than any individual contributor could enter information on the WikiAnswers side.
Well, it depends on what you mean by "contributes." There are many different types of contributions... the fastest ones usually are people chatting on the forums or on the message boards.
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Infants will have the fastest pulse rate.
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is the resting heart rate is fastest in adult life
The amplitude of a sine wave is increasing at its fastest rate at the maximum points (90°, 270°) and decreasing at its fastest rate at the minimum points (0°, 180°).
rate of absorption from fastest to slowest
Fastest transmission rate would be 802.11n
RAM (Random Access Memory) storage devices typically has the fastest transfer rate.
195fps
no
Alum crystals and sugar crystals grow at the same rate at an increasing time rate making them grow the fastest