Just as glucose is the basic building block of carbohydrate, are the basic building blocks of protein.
a. lipids
b. amino acids
c. enzymes
d. collagen

B.) amino acids are the building blocks of proteins.
Lipids are made of nonpolar fatty acids among many others.
Enzymes are proteins that lower the activation rate of many chemical reactions.  
Collagen consists of amino acids forming connective tissues. 

An advantage of an mri over ct scan is d. it produces better images of hard tissues. hope this : )