Explain how a drop of deoxygenated blood flows into the heart and leaves the heart full of oxygen, ready to supply our whole body. Include all four chambers of the heart, all four valves, and don’t forget to mention gas exchange.

Adouble-blinded trial for a new indication is conducted under an ind comparing two (2) marketed drugs, at twice the approved prescribed doses. on day 2, subject 603 had difficulty breathing. although it was life-threatening initially, subject 603 was treated and discharged directly from the emergency department after complete recovery. on day 5, subject 20 had a headache, which led to hospitalization and required blood pressure lowering medications. these episodes cannot be explained on the basis of the pharmacological property of either drug or the subjects' medical histories. the investigator would submit an sae report for