Galaxies are sprawling systems of dust, gas, dark matter, and anywhere from a million to a trillion stars that are held together by gravity. Nearly all large galaxies are thought to also contain supermassive black holes at their centers.
Using kinematic equation, v^2 - u^2 = 2as. 5^2 - 3^2 = 2a x 16. a = 0.5m/s^2. So particle will deaccelerate at 0.5m/s^2. ( v = final velocity, u= initial velocity, a= acceleration, s= displacement.)
One point will be X1,Y1 and the other will be X2,Y2. It does not matter which is which except that X1 and Y1 have to be the same point and X2 and Y2 have to be the same point. For example, let's say you were given (2,3) and (6,8). No matter which point is X1,Y1 and the other is X2,Y2, the slope will still be 5/4.
The rise is the change in y from one point to the other. The run would be the change in x from one point to the other.
This isn't physics, it's biology but basically, when you breath in oxygen, the oxygen goes to the lungs which transfer it to the blood cells. The heart then pumps the blood cells round to the organs, muscles etc and the blood cells drop off the oxygen where necessary, they then pick up carbon dioxide and the heart pumps them to the lungs where the blood cells give the lungs the carbon dioxide and the lungs make you breath the carbon dioxide out (his is a very simplified explanation, I'm not a biologist)