Assertion: water chestnut | /r/MadeOf | copper
Facets:
Source sentences:
text: Water chestnuts contain vitamin B6, potassium, copper, riboflavin, and manganese, along with a smaller array of other vitamins and minerals.
text: The water chestnut plant contains minerals like calcium, phosphorus, iron, copper, manganese, magnesium, sodium, and potassium.