Rank the achievements from 1 (most significant) to 6 (least significant):

· Aztec Chinampas

· Aztec Causeways

· Incan Suspension Bridges

· Incan Terraces

· Mayan Calendar

· Mayan Step-Pyramids

Explanation:

The arrangement goes thus.

1. Incan suspension bridges

2. Aztec causeways

3. Incan terraces

4. Aztec chinampas

5. Mayan step pyramids

6. Mayan calendar

The first two mentioned above were ways or roads to easily passed through water and swamp, which are very important to the next two.

Numbers three and four were created for farming. Which is very important for availability of food.

And the last two were made to know the days of the year.