Assertion: fish's scale | /r/AtLocation | a layer of slime
Facets:
value: often
type: TEMPORAL
value: to help their movement
type: PURPOSE
Source sentences:
text: Fish are covered in scales which are often covered in a layer of slime to help their movement through water.
text: The scales are usually covered with a layer of slime which improves passage through the water, and makes the fish more slippery to a predator.