Which of the following countries can be found in south america? chad slovakia bolivia sudan colombia paraguay

The layers of earth are based on what two sets of characteristics?

Countries that have a traditional economy often develop at a slower pace than countries with a free market economy. true or false

The first atomic explosion was detonated in the desert north of alamogordo, new mexico, on july 16, 1945. what percentage of the strontium-90 ( yr) originally produced by that explosion still remains as of july 16, 2016?