An independent variable in an experiment is the variable that is changed. Here, the type of food is the only thing that is changed and the amount of water, temperature and other variables were kept constant (same). Thus, the independent variable is the type of food Bob is given.
I am not sure but I believe it is B. Precipitation because the definition is: <span>the action or process of precipitating a substance from a solution ^-^ Hope this helps</span>
