Why do we care about chemical reactions?
They help us to fundamentally understand (on a slightly larger scale and a more practical scale than physics) the world around us, and with this you begin to appreciate not only biology more, but all the processes in the world.
What is the single most important quality you can portray to an admissions committee?
That you have a passion for something in life. It shows that you aren't just another resume with some statistics on it; it shows that you will contribute in a meaningful way to their university and ultimately to society.
Why is the equal sign '=' so significant in algebra?
Setting up an equality between two pieces in an equation defines how you can manipulate the variables and constants to extract the information you are looking for.