Do the positive charges of calcium ions and sodium ions make these ions more likely to move into or out of the cell?

Explanation:

As the sodium ions rush back into the cell, they add positive charge to the cell interior, and change the membrane potential from negative to positive. Once the interior of the cell becomes more positively charged, depolarization of the cell is complete, and the channels close again.

good one: produce hormones that plants grow.

bad one: the problem with organic matter is that while plant nutrients are needed for crop growth, they can also stimulate excessive growth of the wrong plants – mainly, algae.