Jax designs an experiment to determine how the amount of sodium chloride affects the boiling point of water. He adds 1 g, 5 g, and 10 g of sodium chloride to three
different beakers, each containing 100 mL of water. There is a fourth beaker that
contains 100 mL water without any sodium chloride. He heats each of the samples
on a Bunsen burner and measures the boiling point with the same thermometer.
Which of the following is/are the control(s) in the experiment? (Choose all that apply)
The thermometer.
The temperature at which the water boils.
The amount of water.
The amount of sodium chloride.