Who has the power to propose constitutional amendments

How can changes in technology or consumer demand make it difficult for people to get jobs? by changing the number or kind of jobs available by making it possible for some people to work fewer hours by making it difficult for people to buy what they want by creating a demand for things that are not available

How would having more railroad tracks be advantageous during a war

The principle that the geoglical processes that we see today have occurred through out earths history is called