What are two chemicals used to remove contaminants from drinking water?
A)Chlorine & Aluminum Sulfate
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B)Copper Chloride & Sodium Nitrate
C)Potassium thiocyanate & ammonia
D)Sodium Chloride & Aluminum

For the first question, the correct answer would be the first and third option. Having data that are accurate would allow us to infer a correct conclusion. Also, the conclusions that are inferred are most of the time judgments from the experiment done and the results obtained. For the second question, the correct answer would be the first option. Before starting any experiment, it is strongly recommended to check other experiment procedures that is the same with the one you are going to execute. This is to ensure that  you are using the right method for your experiment. Also, it would allow you to be more confident in the experiment.