To metabolize something is to break it down into its basic components and use them to create new molecules. This is how the body turns food into energy.
Neuroscientists are scientists who study the brain. They are often interested in understanding how the brain works, and how different parts of the brain work together.
To blissfully is to be very happy and content. When you are blissfully happy, you don't care about anything else in the world.
To tangles is to make something complicated or difficult. When you tangle your hair up in a knot, you are making it difficult to untangle.
To shortchange someone is to give them less than what they deserve. Sometimes people shortchange others because they are not thinking about the consequences of their actions.
To have a checkup is to go to the doctor to have your health checked. A checkup can include anything from a simple blood test to a more complicated surgery.
Unquestionable means completely sure. When you say something is unquestionable, you mean that there is no way that you could be wrong.
Devouring something means to eat or drink it completely. If you devour an entire cake, you've eaten it all.