Need help on numbers 1 through 4

Rutherford's experiment indicated that matter was not as uniform as it appears what part of his experimental results implied this idea

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

Ascientist is measuring the pressure that is exerted by each of the following gases in the atmosphere: carbon dioxide, oxygen, and nitrogen. which term most likely describes what she is measuring?