Why is air less dense than Earths rocks? A : The molecules in rock are larger than the molecules in air.
B: The molecules in rock are smaller than the molecules in air.
C : The molecules in air are further apart than in rocks.
D : The molecules in air are closer together than in rocks. ( this is science by the way )

Astudent pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. she then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. the student performs the experiment one more time but this time she stirs the mixture rapidly. the dependent variable in this experiment is: time for salt to dissolve speed of stirring amount of water mass of salt