Which of the following represents a difference between the mayans and the incas?

the mayans worshipped one god, but the incas worshipped many.
the mayans prayed mainly to the sun god, but the incas prayed to hundreds of gods.
the mayans used complex calendars to plan activities, but the incas practiced divination.
the mayans performed human sacrifices, but the incas did not.

The answer is option 3: The Mayans used complex calendars to plan activities, but the Incas practiced divination.

Ancient Mayan's knowledge of astronomy and math led them to make various calendar systems, such as Haab, Tzolk'in and Long Count, considered some of the most accurate calendars and complex as well, in comparison with today's' world calendar. In overall, they used them to plan social, religious and agricultural activities and to track longer periods of time.

As for the Incas, they tended to practice divination. They sought knowledge of the future or the unknown by "supernatural" means to determine the proper time to make a sacrifice and other social and religious activities.