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: Triton is one of the few moons in the Solar System known to be geologically active (the others being Jupiter's Io and Europa, and Saturn's Enceladus and Titan). As a consequence, its surface is relatively young with few obvious impact craters, and a complex geological history revealed in intricate cryovolcanic and tectonic terrains. Part of its surface has geysers erupting sublimated nitrogen gas, contributing to a tenuous nitrogen atmosphere less than 1 / 70,000 the pressure of Earth's atmosphere at sea level. It is the second-largest planetary moon in relation to its primary, after Earth's moon.
Solution:
what do the moons titan & triton have in common