I have a couple of science questions that I'm stuck on. Help..?
1. Describe how sound is created and gets to our ear for us to hear. Does sound need a medium to travel through?
2.What is wavelength? What does it tell us about the energy of a wave?
3.What is amplitude? What does it tell us about the energy of a wave?
4.What type of waves are light waves? Does light need a medium to travel through?

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.