What is a mole in chemistry? Why are they needed?

Someone whose nitrogen output is greater than their nitrogen intake is said to be in

Because our bodies do not store protein, functional body proteins, such as enzymes and muscle proteins, must be broken down to yield amino acids.

Amino acids are used to make all of the following EXCEPT

Protein-energy malnutrition is only seen in children.

Methyl halides undergo E2 reactions when treated with very strong bases.

Which of the following pairs are the correct terms for the techniques listed?

Which of the following is NOT an elimination product for the following compound?  

Which of the following has a S configuration?  

Of the following, which best describes the mass spectrum (MS) of bromopropane.