Secondary; The events are 100 years apart. There is virtually no chance of it being primary.
Cyanobacteria, also known as "blue-green algae", are the unicellular organisms which are able to produce oxygen.
Approximately 540 years ago, the atmosphere was very poor on oxygen. Cyanobacteria are thought to be responsible for the oxidization of the atmosphere back then, in an event known as <em>"The Great Oxygenation Event"</em>. As a result, Earth's life forms suffered drastic changes in their composition, as they evolved from being <em>anaerobic</em> to becoming organisms <em>highly dependant</em> on oxygen. The oxygenation of the atmosphere would eventually provide the adequate environment in order for the <em>Cambrian Explosion</em>, or the first diversification of living organisms, to happen.
Answer: Consideration of American responses to Nazism during the 1930s and 1940s raises questions about the responsibility to intervene in response to persecution or genocide in another country. As soon as Hitler assumed power in 1933, Americans had access to information about Nazi Germany’s persecution of Jews and other groups. Although some Americans protested Nazism, there was no sustained, nationwide effort in the United States to oppose the Nazi treatment of Jews. Even after the US entered World War II, the government did not make the rescue of Jews a major war aim. (I think this is it i dont know im pretty sure)
Answer:
The answer is D
Explanation:
Being in a valley results in air pollution being contained to an area.
