Synthetic fibers are made of large molecules called __ which are made of smaller repeating units called __ monomers, polymers polymers, monomers proteins, amino acids amino acids, proteins

## Step 1<br />The problem is asking us to identify the correct terms that describe the structure of synthetic fibers. Synthetic fibers are made up of large molecules, which are known as polymers. <br /><br />## Step 2<br />Polymers are large molecules that are made up of smaller repeating units. These smaller repeating units are known as monomers. <br /><br />## Step 3<br />Therefore, the correct answer is "polymers, monomers". The other options, "monomers, polymers" and "proteins, amino acids" and "amino acids, proteins", are incorrect because they do not accurately describe the structure of synthetic fibers.