What i'd the safest way to carry a microscope

How do you date a sample of rock that you suspect as being one of the earliest on earth

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 animal is a producer in this ecosystem