Astudent conducts an experiment to determine how the addition of salt to water affects the density of the water. the student fills 3 beakers with equal amounts of water. he then adds 1 cup of salt to the first beaker, 2 cups of salt to the second beaker and no salt to the third beaker. what is the dependent variable in the student's investigation?
1)the amount of salt in the water.

2)the temperature of the water.

3)the density of the water.

4)the ph of the water.