Heather Sherwood, age 11, of Arlington Heights, Ill., for her question:

WHERE DO PISTACHIO NUTS COME FROM?

Pistachio nuts are sometimes called green almonds. They grow on trees in the eastern Mediterranean area, in southwestern Asia and in California.

Pistachios are about one‑inch long and have smooth, thin and hard shells that tend to open at the edges much, like the shells of oysters. It is covered with a thin, smooth skin that is pale red to yellow. This skin must be removed before the kernel can be processed.

A pistachio kernel may either be eaten as a nut or ground and used as a food flavoring and coloring. Sometimes they are salted in brine while still in their shells.

Pistachio trees do well in dry regions and grow to about 30 feet in height. Trees can be either male or female. In order to produce nuts, the female tree must have a male tree nearby to provide pollen for its flowers.