Which of the following was a feature of the incas? they developed cold-storage techniques. they built underground religious shrines. they lived in long wooden houses. they were skilled mathematicians and astronomers. they lived in multistoried houses.

The Incas were highly advanced in terms of mathematics and astronomy. Their unique architecture  of massive stonework is made possible by their great understanding of mathematics. Inca structures where made of precisely hewn stones that fit together so perfectly without use of mortar. They also understood astronomy and made very accurate calendars.   

c]extended voting rights to african americans

1775 is your answer hope this