Why do some political ideas live on while others are discarded?

How would europe benefit economically from greater unity

Which of the following statements is true of cause and effect relationships

Is the weather changing? consider the data of severe weather that includes tornadoes occurring throughout the u. s. over the last four years. compare the severe weather for the last three years. then compare the first three months of 2017 with that data. based on previous years, what might the prediction be for weather during 2017?