You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.

This list contains the top 25 accounts with the most followers on the social photo-sharing platform Instagram. As of May 2018, the most followed user is Instagram's own account, with over 235 million followers. Selena Gomez is the most followed individual, with over 137 million followers. Ten accounts have exceeded 100 million followers on the site.
Solution: who has the maximum number of followers on instagram
Why? The answer is talking about the Instagram accounts that have the most followers. The question asking about the maximum number of followers. So this is a good example.

New input: The ISS serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology, and other fields. The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars. The ISS maintains an orbit with an altitude of between 330 and 435 km (205 and 270 mi) by means of reboost manoeuvres using the engines of the Zvezda module or visiting spacecraft. It completes 15.54 orbits per day.
Solution:
what is the purpose of the international space station (iss)