When geologists want to study an active earthquake fault, they often rely on a trenching study. ... They brace the walls, if needed, to prevent cave-ins, then they climb down into the trench and carefully map its walls, looking for signs of past earthquakes and ground movement.
Around 400 million years old
Answer:
The 'Middle Ages' are called this because it is the time between the fall of Imperial Rome and the beginning of the Early modern Europe. ... The Dark Ages are given this name because Europe was in disarray in comparison to the orderliness of classical antiquity and life was short and poor.
Answer:
taking data from a population rather than a specific group of people to gather information from
(random and most representative on a large scale of people)
