During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's atmosphere had no free oxygen then. This is about 3.5 billion years ago.
Answer:
1.plateau in the mountains
2. extensive mountain ranges
3.long ridges
4.inca Road system
5.fan-shapred deposit
Some reasons are business travel, family matters, reunions, parties :)
Explanation:
Archeologists list the location of each item because they want to spread knowledge for everyone and lpeven let the future generations know about this..
hope this helps you..
Thanxx
