The cardiovascular and respiratory systems interact to A. send and receive messages to and from all parts of the body.
B. digest and transport food to cells in all parts of the body.
C. transport and exchange gases needed by cells in all parts of the body.
D. sense and react to changes in the environment.

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".