Modern psychological research suggests that when a person feels upset, distressed, and anxious, his body's blood pressure and oxidation will decrease, and when he is happy, the entire metabolism will improve. What do we know from this passage? ['People can adjust their blood pressure by adjusting their mood.', "There is a close relationship between a good mood and a person's physical health.", 'Lower blood pressure and oxidation indicate that the person is in a bad mood.', 'As long as you are happy, you can improve your entire metabolism.']