Answer:
Left atrium
Explanation:
The four pulmonary veins return oxygenated blood to the left atrium.
When someone smokes cigarettes and drinks three alcoholic beverages a day, he or she is contributing to his or her cancer risk via <span>promotion.
Researchers have discovered that the combination of tobacco and alcohol increases the risk of cancer in </span>throat, oral cavity, esophagus and <span>larynx.
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3. positive and a negative ion
To release the energy stored in carbon-containing molecules, such as sugars, autotrophs and heterotrophs break these molecules down in a process called cellular respiration. In this process, the carbons of the molecule are released as carbon dioxide.
