Ummm... good link from mosaic, but I've noticed that anytime anyone, but especially an American (such as myself) comes on to this site with questions that are obviously 'homework', the submitter is instantly criticized for doing so. Although my initial reaction is to be in that camp, isn't the usefulness of this site, carried to its logical conclusion, inclusive of such questions.
Isn't almost every question that is posted on AB, even the 'brick-a-brack' in Chatterbank, can be resolved by Google, Bing or other websites designed especially for that purpose, no? So if our only response is "Go to Google" then this site qould soon dry up... just a tumbleweed blowing across Main Street in Tombstone, Arizona on a hot summer day, propelled by the Santa Ana wind emanating from the Sonoran Desert, causing a feeling of lonelyness and semi-despair known only by the gecko dwelling under the weathered boardwalk on which no one walks... (etc., etc.).