Hi, guys so I'm doing an experiment and need help finding out the types of variables. In my experiment, I am using a narrow straw, a wide straw, and some colored water to find out how different variables affect capillary action. I'm trying to find out what is the controlled variable, independent variable, and dependent variable.

Is it considered muscle s ennervation if sympathetic fibers innervate the vessels within the muscle?

Which of the following systems in absorbing oxygen and releases carbon dioxide

The observations of hooke and van leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory? a. the cell theory stating that all living things are composed of cellsb. the theory of spontaneous generation, which held that life forms could arise spontaneouslyc. the theory of chemotherapy, or use of antimicrobials to destroy pathogenic organismsd. the germ theory of disease and causative agents