World-systems theory<span> (also known as </span>world-systems analysis<span> or </span>the world-systems perspective), <span>is a multidisciplinary, macro-scale approach to </span>world history<span> and </span>social change<span> which emphasizes the </span>world-system<span> (and not </span>nation states<span>) as the primary (but not exclusive) unit of </span>social analysis<span>.</span>
The stock market crashed in 1929 because investors had put too much capital into the stocks by borrowing large amounts of money that they did not truly have.
