The main determinant of skin color is melanin
First of all the reason the graph would be a curve is because, as the time increases the position changes, at first the ball is at a certain point then it starts rolling off a cliff so its moving foward and then the ball starts falling, (If too confusing here is a image http://www.mazzworld.net/U11Image1.gif)
A neuron is nerve cells that transfer information within the body, chemically over short distances, using electrical signals over long ones.
As it turns out, most resting neurons are permeable to Na+ and CL- as well as K+. K+ will try to drag the membrane potential toward its (positive) equilibrium potential, while NA+ try to drag the membrane potential to its negative equilibrium potential.
The real membrane potential will be between NA+ and K+ of equilibrium potential<span>. However, it will be closer to the equilibrium potential of the ion type with higher permeability.</span>
we can get them from eating foods that contain protein bio molecules