The correct answers are "The mayans prayed only to the sun god, while the Incas prayed to hundreds of gods" and "The Mayans had a complex hieroglyphic writing system, while the Incas used quipu to send messages".
While both were polytheisitc and worshipped more than one god, the Mayans primarily prayed to the Sun God who represented the most important religious figure to them. The Incas, on the other hand, prayed to different gods with distinct levels of relevance depending on which region you look at.
In regards to their writing systems, the Mayans used complex symbols in their scripts known as Maya glyphs. The Incas never developed an alphabetic method and instead communicated via a graphic system which used knots made of diverse materials. This method was called Quipu.
Both civilizations performed human sacrifices.
Hope this helps!
