Flying over a desert area in an airplane, two scientists looked down with trained eyes at trees and bushes. After an hour’s flight, one of the scientists wrote in his book, "Look here for probable metal. " Scientists in another airplane, flying over a mountain area, sent a message to other scientists on the ground, "Gold possible. " Walking across hilly ground, four scientists reported, "This ground should be searched for metal. " From an airplane over a hilly wasteland a scientist sent back by radio one word: "Uranium. "
None of the scientists had X-ray eyes: they had no magic power of looking down below the earth’s surface. They were merely putting to use one of the newest methods of locating minerals in the ground... trees and plants as signs that certain minerals may lie beneath the ground on which the trees and plants are growing.
This newest method of searching for minerals is based on the fact that mineral
A. there were larger amounts of gold in the branches than in the seeds
B. there were smaller amounts of gold in the roots than in the branches
C. there were less amounts of gold in the seeds growing on the ends of branches than seeds growing nearest to the tree trunks
D. there was more gold in the branches than in the roots
某消防安全重点单位一幢6层建筑，每层建筑面积1500m2，建筑高度23m。设有集中空调系统、消火栓给水系统和两座开敞楼梯，建筑物每层的使用功能是：1层为印刷车间，2～5层为办公用房，6层为员工集体宿舍。
回答下列问题：
41~45题基于以下共同的题干：
G、H、J、K、L、M和O七人结伴出游。在他们4天的露营生活中，每天要安排两个人值班为大家做饭。要求这4天的人员安排不能重复，且恰好有一人值班两天。此外，值班安排还须满足下列条件：
（1）J要排在H值班的次日。
（2）值班两天的按个人必须排在第四天，不能排在第三天。
（3）G必须与J和O的某一个人排在同一天。
（4）第一天或第二天至少有一天安排K。
（5）O必须排在第三天。
以下哪个人必须排在第二天（）？
我来回答:
