Jae Kwon gave examples in Paragraph 4_________.
A. to show chemical batteries are widely applied.
B. to introduce nuclear batteries can be safely used.
C. to describe a nuclear-powered system.
D. to introduce various energy sources.
正确答案：B
细节理解题根据文章第四段可知Kwon举例的目的是为了说明原子能电池是安全的所以B项正确
