Assertion: parrot's feather | /r/MadeOf | keratin
Facets:
value: firstly
type: MANNER
Source sentences:
text: Feathers are made of keratin which is the same substance that human hair and nails are made from.
text: Firstly, feathers are made from keratin in which coloured pigments are present.
text: Feathers are made of keratin, the same material out of which a reptile’s scales and claws are made.
text: Firstly, feathers are made from keratin in which coloured pigments are present.