Which type of rock forms from the fragments of other rocks?

You may expect bonds between two atoms which each have n covalent lonic metallic hydrogen

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.

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )