Answer:
 hemoglobin
Explanation:
Cytoplasm of RBCs contain large amount of hemoglobin which contain iron binds to haem group. it carry and transport oxygen from lungs to all parts of body and return carbondioxide back to the lungs from the different tissues.
Normal level of hemoglobin for men= 13.5 to 17.5 g/dl and for women =12.0 to 15.5 g/dl
Low level of hemoglobin is the indication of anemia
 
        
             
        
        
        
Photosynthesis is the opposite of cellular respiration. 
glucose is converted into ATP during cellular respiration.
Light energy + Oxygen = Glucose 
We breathout CO2 during the process of cellular respiration.
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Answer:
Because igneous Rock is separated into different minerals. Radio carbon dating works by measuring the amount of carbon dioxide.
 
        
             
        
        
        
The first answer is correct, the second one is D.