Acids have a ph of 6 and below whole bases have a ph of 8 and above. If a human has to much acid in their stomach they can take a pill that will lower it back to its normal ph level
        
                    
             
        
        
        
The first one is second succession. The second question I don't understand.
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Answer: B. under use; it is a scarce resource.
Explanation:
Early settlers in the town of Dry Gulch drilled wells to pump as much water as they wanted from the single aquifer beneath the town. (An aquifer is an underground body of water.) As more people settled in Dry Gulch, the aquifer level fell and new wells had to be drilled deeper at higher cost.Residents of Dry Gulch have a private incentive to under use water because it is a scarce resource.
 
        
             
        
        
        
The generic name of poisonous chemicals, very often used in commercial agriculture that are used to kill organisms that either reduce the yield of crops or are harmful to animals are pesticides.
Pesticides are the chemicals used to kill the pests affecting the growth and yield of the crops. Pesticide is a broad term covering various small terms according to the pest being killed. For example insecticide, nematicide, avicide, rodenticide, bactericide, etc. Some chemicals used as pesticides are boric acid, Acephate, Deet, Propoxur, glyphosate, etc. 
Commercial agriculture means growing of crops so as to sell them in the market to be utilized by the wide population of any area. Any crop can be grown at the commercial level. These crops do not reach the customers directly by the farmers, instead they are sold to whole-sellers first. 
To know more about pesticides, here
brainly.com/question/1386090
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More than likely mutation