Presence of inorganic molecules with lightning and intense radiation
Explanation:
This process of formation of organic molecules from inorganic molecules is called abiogenesis. It is believed that this is how the first organic molecules were created in early earth about 3.8 billion years ago. The classic 1952 Miller–Urey experiment attempted to replicate the condition of early earth. They replicated lightning strikes (using electric parks) in a glass with greenhouse gases believed to have been the major constituents of early earth's atmosphere like methane. They were able to form primitive organic molecules from this experiment.
Answer: Blood flows through your heart and lungs in four steps: The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle through the tricuspid valve. The right ventricle pumps the oxygen-poor blood to the lungs through the pulmonary valve.