A student conducts an experiment to determine how the temperature of water affects the time for salt to dissolve in 100 mL of water. The student makes one measurement for each temperature. What is one way that the student could improve the experiment? perform one trial for each measurement but use a different volume of water for each test use a different type of salt for each temperature of water use a different timer for each temperature of water perform multiple trials for each measurement instead of just one

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.