The text boxes in the left panel have been placed in a random order. Restore the original order by dragging the text boxes from the left panel to the right panel.
d) Also, ivory tends to chip more easily than plastic.
a) Traditionally, the black keys were made from ebony and the white keys were covered with strips of ivory, but since ivory-yielding species are now endangered and protected by treaty, plastics are now almost exclusively used.
c) Spruce is normally used in high-quality pianos.
b) Piano keys are generally made of spruce or basswood, for lightness.