Please help, I only have one attempt.

Maria wants to determine which type of disinfectant kills the most bacteria. which of the following is the best way for maria to determine this? a. ask ten different companies that make disinfectants which type is best. b. put the same amount and species of bacteria on ten identical plates, and add ten different kinds of disinfectant to each plate. c. interview ten different people to determine which type of disinfectant they prefer. d. put the same amount and species of bacteria on ten identical plates, and add a different disinfectant to each plate.

When you perform this reaction, what could remain at the end of the reaction? check all that apply. excess reactant aqueous copper chloride excess reactant aluminum oxygen product solid copper carbon dioxide product aqueous aluminum chloride water

If a solution had a ph of 7 what is the solution