What is the difference between true north and magnetic north

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

What is a dendrite and what does it do?

Which of the following cell structures is significantly different between gram- positive and gram-negative bacteria?