Protective sacs aorta 2. carries blood to the body pericardium
3. carries blood to the lungs heart chambers
4. open and close valves
5. atria and ventricles pulmonary

Which system revise and send electrical signals throughout the body

Pepsin is an enzyme in the stomach that breaks polypeptides into amino acids. pepsin functions best at a ph of around 1.5. what would be the most likely result if the ph of the stomach were increased to 5

Why are scientists concerned about the depletion of the ozone levels in the stratosphere?