Again, to manipulate an independent variable means to change its level systematically so that different groups of participants are exposed to different levels of that variable, or the same group of participants is exposed to different levels at different times.
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</span><span>a bitter greenish-brown alkaline fluid that aids digestion and is secreted by the liver and stored in the gallbladder. </span> So the anwser is B.
Intensity is the amount of physical power (expressed as a percentage of the maximal oxygen consumption) that the body uses when performing an activity.
