题目

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri(MU)researchers are developing a nuclear energy source that is smaller, lighter and more efficient. “To provide enough power, we need certain methods with high energy density (密度),” said Jae Kwon, assistant professor of electrical and computer engineering at MU. “The radioisotope (放射性同位素)battery can provid读北极地区示意图，下列说法正确的（）A．大部分地区终年冰雪覆盖，是年平均气温最低的地区B．居住着因纽特人，耐寒的北极熊和企鹅也生活在这里C．甲是格陵兰岛，乙是跨经度最广的国家俄罗斯D．中国黄河站位于北极圈以外，无极昼极夜现象