Whats the fastest way to improve at anything, based off of science

What is not true about me to metabolisms

Why would one lymph node in the neck be swollen and not the other? what causes them to swell?

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the dependent variable in galileo's experiment?