Whst the person feels​

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

Analyze why south america is a place of ethnic diversity.

This is the mountain range known as the alps. which of these statements regarding the alps is true? a) the alps are the largest mountain range in asia. b) the alps protect the roman empire from invasion. c) the alps were key in preventing england from being conquered in warfare. d) the alps prevented the roman empire from taking control of most of europe.