Make calendars the Mayans studied the pattern of the moon, Sun and stars making a calendar (however the months July and August were added by Julius Ceaser)
The answer here is meta-analysis.
We can see here that Dr O'Connor is using meta-analysis because she is examining the 170 studies that have been done on the topic to find out the truth that lies behind theses similar studies. Meta-analysis in essence is a statistical analysis done on the results of the previous studies on a certain topic or in a certain field as it combines all of those findings to get an overall result.
It takes 224.7 earth days to orbit the sun once.
Revolutionary war is what brought the USA together as a slave free nation.
