Which of the following is not a principle of natural selection?

In the context of the neural impulse, which of the following is true about the depolarization of neuron membranes?

How does climate change affect producers?

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?