<span>In the "all or none" law of muscle contraction, it states that when the stimulus applied exceeds threshold then the the nerve sending signals to a few muscle fibers will give a complete response; contraction. Graded response is dependent on how many motor units have been recruited. The more motor units, the greater the force in the contraction.</span>
Structurally, DNA and RNA are nearly identical. However, there are three fundamental differences that account for the very different functions of the two molecules. RNA has a ribose sugar instead of deoxyribose sugar like DNA.