English is the national language of the United States.
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.
Answer:
troposphere - Responsible for earth's weather
exosphere - Air mergers into space
ionosphere - Used to send radio signals
stratosphere - Characterized by strong, steady winds
ozone layer - Protects earth from UV radiation
mesosphere - coldest layer
Explanation:
Answer:
No
Explanation:
Since the heart is a muscle that is pumping (literally requesting blood) through the body atria and ventricles altérnate pumping.