Answer:
Carbon dioxide is a gas consisting of one part carbon and two parts oxygen. It is one of the most important gases on the earth because plants use it to produce carbohydrates in a process called photosynthesis
Explanation:
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<span>The circulatory system is vital in the exchange of oxygen with the cells in the animal's body because there is no living creature that can survive without oxygen, it keeps the body active.
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Answer: False 
<span>Genes do play a role in the development of obesity but a genetically predisposed person can still improve his overall health through moderate lifestyle changes.</span>
<span>Obese people may change their weight slowly by altering lifestyle habits with the support of their family and friends. Even if weight remains unchanged, overall health will improve with moderate lifestyle changes.</span>
 
        
        
        
Answer:
Leukocytes are also called white blood cells. These cells have a nucleus, unlike red blood cells that lack a nucleus. Also unlike red blood cells, white blood cells do not contain hemoglobin, which means they're not involved in the transport of oxygen.