By 1860, the settlement of the American West along with timber shortages in the East converged with ever-widening impact on the pine forests of the Great Lakes states. Over the next 30 years, lumbering became a full-fledged enterprise in Michigan, Wisconsin, and Minnesota. Newly formed lumbering corporations bought up huge tracts of pineland and set about systematically cutting the trees. Both the colonists and the later industrialists saw timber as a commodity, but the latter group adopted a far more thorough and calculating approach to removing trees. In this sense, what happened between 1860 and 1890 represented a significant break with the past. No longer were farmers in search of extra income the main source for shingles, firewood, and other wood products. By the 1870s, farmers and city dwellers alike purchased forest products from large manufacturing companies located in the Great Lakes states rather than chopping wood themselves or buying it locally.
Q.What can be inferred from p2, about timber in America before the year 1860?
A. Farmers of the American West earned most of their income by selling timber to newly arrived settlers.
B. Timber came primarily from farmers who wished to supplement their income.
C. Timber was much more expensive before the year 1860 because it was less readily available.
D. Timber came primarily from large manufacturing companies in the East.
B가답인데 왜 답인지 모르겠습니다..
Q. According to p2, what suggests that human activity played a role in the extinction of mammals about 11,000 years ago?
A. Climate changes that would have favored human population expansion occurred at the time of the extinctions.
B. The presence of human hunters had caused animal extinctions in other time periods.
C. There was a pattern of climate change earlier than 11,000 years ago that had not caused animal extinctions.
D. Harmful climate changes 11,000 years ago would have required humans to hunt larger numbers of animals for food.
답이 c 인데 이것도 모르겠어요..