What are the two types of moving electrical charges?

What does the process of natural selection involve

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.

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process