题目

阅读理解400­year­old plants from the Little Ice Age were brought back to life, which could help us understand how the Earth will deal with climate change.Moss (藓类植物) found buried beneath the Teardrop Glacier (冰川) on Ellesmere Island in Canada has been brought back to life. Findings suggest that these plants could help repopulate regions exposed by melting ice caps. Plants that were buried beneath thick ice in Canada more than 400 years ago and were thought to have frozen to death have been brought back to life by Canadian scientists. Samples of the moss plant, covered by the 6．已知四棱锥P-ABCD中，AD=2BC，且AD∥BC，点M，N分别是PB，PD中点，平面MNC交PA于Q．（1）证明：NC∥平面PAB（2）试确定Q点的位置，并证明你的结论．