How do some cells become brain cells and other become skin cells, when the dna in all exactly the same. in other words, if the instructions are exactly the same, how does one cell be cell and another a skin cell?

Why aren't the stains like crystal violet and safranin washed away with water during simple staining?

Energy derived from hot rocks and fluids beneath the earth’s surface is

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi,r^3 , where r is the sphere’s radius.