You can speak to people on other side of the earth over the telephone with help of a satellite. They can help to take photos on the earth and produce maps. Some pictures taking by satellites show us the exact place where different metals can be found. They can also tell the differences between healthy plants or poor ones. This is a great help to the scientists work in forestry and in agriculture. Satellites benefit by out daily life. For example, satellites for broadcasting are used to sending radio and TV programmes from one part of the world to other. It is the satellites to make our world seem smaller.

以下哪项诊断原发闭经最有意义（）

A.绝经期无月经

B.妊娠期无月经

C.女子年逾16周岁月经尚未来潮

D.月经周期建立后又中断6个月以上

E.哺乳期无月经