Various reasons why five trained individuals might come up with different readings are - while carrying out an experiment, the accuracy with which each individual perform an experiment varies. The readings in different instruments used while performing an experiment also differs. 
There is certain percentage of error that occurs while carrying out an experiment by each of the individual. Physical conditions such as temperature, pressure changes from one place to another where the experiments are being carried out. 
 
        
             
        
        
        
Building walls and houses, fire pits, construction materials, decoration etc...
 
        
             
        
        
        
A prothallium, or prothallus<span> is usually the </span>gametophyte<span> stage in the life of a </span>fern<span> or other pteridophyte. Occasionally the term is also used to describe the young </span>gametophyte<span> of a liverwort or peat moss as well.</span>
        
                    
             
        
        
        
Answer: Nitrogen-fixing Bacteria 
Explanation:
In the Nitrogen cycle, nitrogen fixing bacteria are very important in ensuring that plants get nitrogen to enable them grow and as animals have to eat plants, these bacteria are essential for our survival as well. 
Plants are unable to use atmospheric nitrogen but nitrogen-fixing bacteria are able to synthesize ammonia from atmospheric nitrogen. They can then convert this to Nitrites and Nitrates which are more useful to plants and animals by extension. 
 
        
             
        
        
        
Answer:
The correct answer is A. Substrate-level phosphorylation
Explanation:
During the substrate-level phosphorylation, phosphoryl group is directly added to ADP or GDP to form ATP or GTP from phosphorylated intermediate rather than from inorganic phosphate like in case of oxidative phosphorylation.
So in glycolysis 4 ATP are produced by substrate-level phosphorylation. Apart from the 4 ATP, 2NADH are also produced during the glycolysis which is used during the oxidative phosphorylation and produce 4-6 ATP.
So ATP made during glycolysis is generated by substrate-level phosphorylation as ATP is produced by direct addition of phosphoryl group from intermediates.