The answer is C. nitrogen.
Plants are main producers in ecosystems so, primary productivity of ecosystems depends on them. Carbon is necessary for plants, but it is widely present in plants. On the other hand, calcium and sodium are not as essential. However, nitrogen is important for plants because it is necessary to make proteins. Proteins take part in many different processes such as photosynthesis (this is actually primary productivity). But, nitrogen is not available to plants, they cannot absorb it simply from the air but rely on some symbiotic bacteria which are able to.
        
             
        
        
        
Answer:
The answer is Chloroplast.
Explanation:
Chloroplast is a structure in green plant cells which contain a substance called chlorophyll which give plant leaves their green color.
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Answer:
The 13 essential vitamins your body needs are vitamins. 
Explanation:
A, C, D, E, K and the B vitamins: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyroxidine (B6), biotin (B7), folate (B9) and cobalamin (B12). The four fat-soluble vitamins—A, D, E, and K—are stored in the body's fatty tissues.
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The polymer that is responsible for your inheritance is DNA. DNA stands
for deoxyribonucleic acid, and is responsible for all the characteristics
that living things inhabit.
        
                    
             
        
        
        
Answer:
Even though they might have a common ancestor there might be a closer common ancestor to the original ancestors than the organism you're looking at. 
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Explanation: