Peanut butter and jelly sandwich

Consisting typically of two slices of bread, the sandwich is usually prepared by smearing one slice with peanut butter[?], which conveniently sticks to the bread. The other is smeared with any of several flavors of jelly (often grape-flavored), jam, marmalade, or preserves. Of great advantage is that the peanut butter will not slide or drip off from the bread when it is put together with the jelly slice, allowing even a child to master its preparation.

Another advantage, compared to, say, a ham and cheese[?] with mayonnaise, is that it will stay fresh for a longer time. A schoolchild who brings the sandwich to school in an unrefrigerated lunchbox[?] could safely eat it as an after-school snack[?]. The United States Department of Defense is researching ways of preserving a PBJ for up to 3 years for its combat troops[?] in the field.