Please help me. I will give you a brainlist, and 10 pint or 5. Please I beg you.

Afamily is one another name for a group on the table of elements.

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 does the symbol (–hfus) indicate in a phase change?