Well, biotic factors are living things in an ecosystem such as animals or insects. Abiotic factors are non living things in an ecosystem such as sunlight or temperature. I would say biotic factors would be more harmful since this includes bacteria or other diseases, not many abiotic factors would pose a great threat to the entire human species. Hope this helped.
        
             
        
        
        
...respiration! 
Respiration is the biochemical process in which the cells of an organism obtain energy by combining oxygen and glucose, resulting in the release of carbon dioxide, water, and ATP (the currency of energy in cells). Source: https://study.com/academy/lesson/what-is-respiration-definition-process-equation.html
I hope that helps! :)
 
        
             
        
        
        
D - an increase in tree cover in the tundra. 
 
        
                    
             
        
        
        
The release of pyrophosphate from the incoming nucleotide, and then hydrolysis of the pyrophosphate to inorganic phosphate provides energy for the addition of nucleotide onto a DNA strand.
Nucleotides are linked together by a condensation event that yields a tiny, stable molecule. But the released molecule is pyrophosphate, not water. A good amount of free energy is released when water is added to pyrophosphate.
The high-energy link between the ejected beta and gamma phosphates stores the energy for each incoming nucleotide's addition. The subsequent hydrolysis that occurs drives the process. A substantially greater quantity of energy is released when two phosphates are separated into individual phosphates.
Learn more about nucleotides here:
brainly.com/question/13185536
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