How did the action's of Bartolome de last casa lead to the start of African slavery in the Americad

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

Eter lives in a beautiful region. peter and other residents of his region use water from the river that flows through their region. recently, mark industries decided to set up their chemical plant near that river. peter realized that the waste from the chemical plant would pollute the river. he decided to seek a legal ordinance that would restrict the use of land near that river for specific use only. which type of zoning will peter and his region?

How do direct democracry and representative democary differ