Explanation: Germany had suffered a great economic depression in the 1930s as a result of being held financially responsible for the aftermath of World War One. The Nazi Party presented "Jews" as the cause for the many political, social, and economic problems that Germany faced after World War One. Adolf Hitler specifically developed his own theories of racial struggle and emphasized the intent of the Jews to survive at the expense of many German's well-being. The Nazi Party adopted these ideals and from 1933-1938 ordered mass book burnings and boycotts that targeted Jews, which rapidly aided the transition of genocide becoming a major focus of the Nazi Party. This harsh antisemitism mainly sprung from the Nazi Party's agenda to seize power and blame Jews for much of their financial problems.
It indicates that the river is very clean since if you have fish and other invertebrates, you have to have some algae and water plants. If the river is dirty, little plants will grow and there won't be many fish and other invertebrates.
