Q:If you watch the sky for about an hour after the sun goes down , you may see some " moving stars". But they're not really stars. They're man--made satellites . And the biggest of all is the International Space Station(ISS). From May to July is the best season to watch the ISS flying over the earth. And people can see it with their eyes. The ISS is the biggest satellite and scientists want to live on it. They think that the best way to learn more about space is to live there. When the space station is finished , it will be like a city in space. People will stay and study there with many of the things they have at home. Laboratories, living rooms and power stations are being built. The ISS is the most expensive space program. Billions of dollars are being spent on it every year. Scientists hope that the ISS will be _ for future space exploration . "The ISS will help us understand the human body better, explore space and study the earth. It can help us make life on the earth better, " said Kathryn Clark , an ISS scientist. Sixteen countries are part of the program: the US, Russia, Canada, Japan, Brazil and 11 European countries. China isn't an ISS country , but it has helped with some of the experiments. In 2003 , China sent some rice up to the ISS to find out what space would do to it. ,. China sent some rice up to the ISS in order to _ . A) be used as astronauts' food B) sell it to aliens C) do some science experiments D) make it grow better in space
A:
C