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.
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B. Scientific Method.
Explanation:
The scientific method is a way of answering questions, or rather experimenting to build a hypothesis. It had the following steps, observation, forming a question, then hypothesis, a prediction based on the hypothesis, testing the prediction, and using the results of the test to adjust the hypothesis if needed, or to make a new one with new predictions.
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Most colonists had faced difficult lives in Britain, Ireland, Scotland, or Germany. They came to the Americas to escape poverty, warfare, political turmoil, famine and disease. They believed colonial life offered new opportunities.
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tariff of <span>Abomination.
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For his part, Hitler wanted a nonaggression pact with the Soviet Union so that his armies could invade Poland virtually unopposed by a major power, after which Germany could deal with the forces of France and Britain in the west without having to simultaneously fight the Soviet Union on a second front in the east.
