which of the following describes a key difference among the 20 amino acids that are used to make proteins?

A key difference among the 20 amino acids used to make proteins is that some amino acids are hydrophobic. All 20 amino acids share the same basic structure including a central carbon, an amino group, a carboxyl group, and an R-group (side chain), but the R-groups vary and determine their properties, such as hydrophobicity or hydrophilicity. This hydrophobicity influences protein structure and function significantly because hydrophobic amino acids tend to cluster away from water, affecting how proteins fold and interact.