The particles are locked in space. they are compactly arranged.
The answer is a
Hope this helped
Valine, Leucine & Isoleucine
Alanine
Arginine
Glutamine
Lysine
Aspartic acid
Glutamic Acid
Proline
Cysteine
Threonine
Methionine
Histidine
Phenylalanine
Tyrosine
Tryptophan
Asparagine
Glycine
Serine