What two factors affect the speed of a sound wave as it travels through a medium?
the energy transferred by the wave and the density of the medium
o the type of medium and the energy transferred by the wave
the type of medium and the temperature of the medium
o the temperature of the medium and the energy transferred by the wave

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.