By the end of the Middle Ages, Arthur's fifth-century foot soldiers had become knights on horses; his fortified hills had become grand castles; and his court had become Camelot, a chivalric utopia. What is the appositive in the sentence and what does it modify?

Consider the title and souce of the following articles. which one is most likely to exhibit a bias? (a) how to roast beef," by the food editor of a magazine (b) americans experiencing greater fatigue than previous generations, " by a harvard researcher (c) "americans' worsening eyesight not related to computer screen usage," by the public relations director of a major computer manufacturer (d) "sharing the burden: a history of cooperation," by a college professor