What are two continents whose edges are not all on plate boundaries?

Drastic boundary changes can occur for all of the following reasons except for a. a shift in the way a river flows b. the collapse of a government system c. a conflict between two neighboring groups d. one country's decision to sell land to another country select the best answer from the choices provide

The causes of the failure of the league of nations

Which of the following is a way that advancements in technology improve humans' ability to measure air quality and protect human health?