Question

astronauts and scientists conduct research studies aboard the international space station, a satellite that was built by
the united nations.
the united states.
twenty nations.
sixteen nations.

Explanation:

The International Space Station (ISS) is a collaborative project. It was built by sixteen nations. These include the United States, Russia, Canada, Japan, and eleven member states of the European Space Agency (Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom). The United Nations was not the builder. The United States was one of the major partners but not the sole builder. And it was sixteen, not twenty, nations involved in its construction.

Answer:

sixteen nations.