13. how do sodium-potassium pumps support the efficient functioning of cells?

Lets consider the neurons.

Explanation:

When nothing happens (no stimulus), potassium ions and sodium ions diffuse in accordance with a concentration gradient. They use some (there aren't many open) ion channels.

The role of pumps is to put them back. Otherwise neuron would lose it's ability to transfer the impuls.

the index of refraction of the second medium is higher. i just took the test trust me !

there’s no image attached but i can if you want: )