Which of the following is most easily changed to alter resistance?
a. vessel length
b. blood viscosity
c. vessel diameter
d. temperature

Answer is C.

Explanation:

A. The vessel length is pretty much constant. The body can't length or shorten blood vessels.

B. Blood viscosity is also fairly constant because the composition of blood cannot change quickly enough to change resistance as needed.

C. This is the main way resistance is controlled. The smooth muscle surrounding blood vessels can rapidly respond to hormonal or metabolic stimuli and contract/relax to adjust diameter.

D. Again, temperature is fairly constant in the body and would not be a good way to alter resistance.

propane is burned to provide the heat in many cooking grills. the chemical reaction for this process is shown in the equation below.

c3h8 + 5o2 ? 3 co2 + 4h2o + energy

what are the products in this chemical reaction?

3co2 + 4h2o + energy