What is the basic molecule in chromosomes?

How does human environment effect the biosphere

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 the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic