Question

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

Explanation:

The device shown is a sphygmomanometer, which measures blood pressure as the heart contracts and relaxes (systolic and diastolic pressure).

Answer:

B. measures the pressure of blood when the heart contracts and relaxes