In class one day, a student heard the teacher say that "like dissolves like." To test this theory, she performed the following experiment:

Four 250 mL beakers containing 100 mL of water each were placed side by side on a table.

Then, she put 50 g sodium chloride, 50 g vegetable oil, 50 g sugar, and 50 g glycerin into the first, second, third, and fourth beakers, respectively.

Finally, she stirred each beaker for exactly 2 minutes using a different stirring rod for each beaker.

Which of the following factors was the variable in her experiment?In class one day, a student heard the teacher say that "like dissolves like." To test this theory, she performed the following experiment:

Four 250 mL beakers containing 100 mL of water each were placed side by side on a table.

Then, she put 50 g sodium chloride, 50 g vegetable oil, 50 g sugar, and 50 g glycerin into the first, second, third, and fourth beakers, respectively.

Finally, she stirred each beaker for exactly 2 minutes using a different stirring rod for each beaker.

Which of the following factors was the variable in her experiment?