Repolarization begins as: Group of answer choices sodium ions follow their electrochemical gradient into the cell. voltage-gated potassium ion channels begin to close. voltage-gated sodium ion channels activate. voltage-gated potassium ion channels activate.

The table below shows the elements that mainly comprise each of the four layers of earth: elements in layers layer main elements crust oxygen, silicon mantle iron, magnesium outer core iron, nickel inner core iron which of these elements make up the layer that is 0.2 to 1.1 percent of earth's total diameter?