Which sentence has the correct subject-verb agreement?

scientists who study the universe has several theories about the rings around planets.
saturn, which is the sixth planet from the sun, rotate every 10 hours and 14 minutes.
saturn, along with jupiter and uranus, has rings that encircle the planet.

the reason some people sacrifice their own life for another person's life could be that they are in love with them and would do anything to keep them safe a protected even if that means risking their life in the process

huck's relationship with food is a prominent theme throughout the novel, and during his time on jackson's island and working his way down river, huck revels in and enjoys his ad hoc dining. in the first chapter, we observe huck is ironically trapped in a "civilized" world, when he would prefer to live freely in nature.