What types of cells would NOT be found in the CIRCULATORY system? * 1:Muscle cells
2:Nerve cells
3:Blood cells
4:Skin cells

Aresearcher is interested in the effect of exercise on stamina in elderly patients. the patients are randomly assigned to be in a high-exercise or low-exercise training program. at the end of the program, their stamina is measured by seeing how long they can walk comfortably on a treadmill. identify the independent variable. identify the dependent variable and explain how it was measure.