Where it receives blood from left ventricle and where transport it to ?

The image below shows a common blood pressure gauge. what does this device do? a. measures the level of oxygen present in the blood b. measures the pressure of blood when the lungs expand and compress c. measures the electrical activity of the heart d. measures the pressure of blood when the heart contracts and relaxes

Which of the following is a testable hypotheses?

What are some natural processes that represent physical and chemical changes?