How does a training change a traditional profession into a modern profession

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?

11. why do citizens have to register to vote?

What trade did europeans want most before the 1800s ivory wood slaves gold