"in the experimental setup below, which substance would be used to prove that the gas produced by the yeast in the vacuum bottle could change the ph of the liquid in the flask?
(1)an indicator
(2)a chemical messenger
(3)an enzyme
(4)a salt solution"

Two nursing assistants are in line to wash their hands at a hospital after leaving a patient in an isolation room. the first na washes her hands and then uses her hands to turn off the faucet before drying them with a paper towel. the second na turns on the water with her hands and then proceeds to wash and dry her hands with a paper towel. which statement best describes errors demonstrated by the nursing assistants? the first na did not ensure a clean hand-washing environment, and the second na did not properly turn off the water the first na did not properly turn off the water, and the second na did not ensure a clean hand-washing environment. the first na did not properly turn off the water, and the second na did not properly use paper towels. the first na did not properly use paper towels, and the second na did not ensure a clean hand-washing environment.