题目

短文填空 Each year (thousand) of tourists visit the polar regions of the Arctic and Antarctica. But the increasing number of people traveling to the ends of the Earth can have negative effect on fragile ecosystems. Should tourists (allow) to visit polar regions? About 40,000 tourists visit Antarctica each year. More than five million travel to the Arctic and sub-Arctic. Transporting tourists to the regions (increase) ship and airplane traffic, adding to the risk of pollution, oil spills, and other (environment) damage. Because the places where wildlife is accessible (be) few in number, tou如图是我国人口数量增长图，根据这个统计图回答问题：（1）1950年到1990年我国人口增长多少亿？（2）从1990年到2000年这十年间，我国人口平均每五年的增长率是多少？（供参考使用数据：1.0872=1.182）