The study of structure and behavior of the physical and natural world through observation and experiments
It applied to all states EXCEPT Kentucky, Maryland<span>, </span>Delaware<span>, </span>Missouri<span>, or </span><span>Tennessee.</span>
World War II effectively began when German troops crossed the borders of Poland.
This campaign, also known as 'the invasion of Poland' started on 1 September and ended on 6 October 1939 with Germany annexing Poland.