Assertion: collagen's amino acid | /r/HasProperty | needed
Facets:
Source sentences:
text: Approximately 21 amino acids are needed to form collagen, and they can be found in protein-rich foods.
text: Around 21 amino acids are needed to form it and can be found in protein-rich foods.
text: Roughly 20 amino acids are needed to form collagen, and they can be found in protein-rich foods.