How does each of the economic system differ?

Mr. mann's science students were experimenting with speed. they set up a 1 meter (100 cm) track. the students used balls instead of cars. the balls were different sizes and made of different materials. four at a time, students rolled balls around the track to see which had the fastest and slowest speeds. some of their data are shown in the table. which ball will take the longest to complete one lap around the track?

What role did natural resources play in african politics?

Account for differences in percentage population growth rates between more economically developed countries and less economically developed countries