How many miles is two inches

In which research method does a researcher change the value of one variable to determine how the change affects another variable? a. experiment b. observational research c. survey d. case study

Which action best represents the policy of appeasement followed by britain and france prior to the start of world war ii? (a)allowing hitler to annex the sudetenland as part of the munich agreement (b)signing the nazi-soviet pact binding hitler and stalin to peaceful relations (c)sending troops to fight with the liberals during the spanish civil war (d)forbidding the sale of arms to any nation at war

If both the president and the vice president can no longer serve, who will become the next head of state?