Explain the difference between a parody and a satire. Give an example of each from a work by Voltaire and from one by Cervantes.
Parody is often an element of satire, so it is not necessary to separate the two, but I've done so to help with your question.
Satire--Voltaire's Candide is an effective example of classical satire. A true satire seeks to mock and ridicule aspects of society or human nature in order to promote change. In Candide, Voltaire satirizes the unequal social classes of his day and the hypocrisy of most organized religion. At the novel's end, Candide lives a simply but happy life away from religious or philosophical debate and class warfare.
Parody--Cervantes Don Quixote demonstrates the use of parody which also mocks and ridicules but more through imitation and mimicry than classical satire. Don Quixote imitates the style and unrealistic nature of the knight romances that were popular during Cervantes' era. Imitating a chivalrous knight, Don Quixote rides out to do battle. The parody includes him taking on windmills instead of other knights in a jousting match. That being said, Don Quixote (as a whole) also includes quite a bit of classical satire. Like Voltaire, Cervantes saw problems with the social and religious structures of his day and uses his novel to ridicule those problems.