proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macro molecules. the functions of proteins are very diverse because there are 20 different chemically distinct amino acids that form long chains, and the amino acids can be in any order. For example, proteins can function as enzymes or hormones.
The underside of epithelial tissue<span> is anchored by a basement membrane to connective </span>tissue<span>.</span>
A secondary source is anything written after the fact
Can you provide a picture
