56. On the whole, 1491 is a book mainly about America's_______ . (A). life-styles (B). population (C). history (D). agriculture

58. From this passage, we can learn______ . (A). people settled in the Americas a little earlier than 1492 (B). North Americans were the tallest in the 18th century in the world (C). Mesoamerican farmers knew genetic engineering 5,000 years ago (D). the population in the Americas was smaller than that in (E)urope in 1492