How were civilizations in Mesoamerica and the Andean region able to develop in different environments—that is, ones without major rivers—than those in Afroeurasia?

Answer should be a. i believe

Mean is the same thing as averageexamplethe mean of 30 and 40 is 35 because (30+40)/2=70/2=35mean absolue deviation is when you take the mean of the setthen you find the diffference of each number of the set then take the mean of thatex if yo uhave 1,2,3,4,5 and the mean is 3, then ou find the absolute value of the difference of each|1-3|=2|2-3|=1|3-3|=0|4-3|=1|5-3|=2add them and divide by 5(2+1+0+1+2)/5=6/5= mad=6/5

Answer high levels of muscular fitness can improve your self image and improve or prevent chronic disease as diabetes, osteoporosis,and cardiovascular disease;