The first tree was displayed at the White House in 1889 it was a Christmas tree
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:
Fort Duquesne
Explanation:
Fort Duquesne was the location for the scene of fighting that led to the start of the French and Indian War.
The British went on the offensive on September 1758 which led to the loss of lives on both sides even though the attack was unsuccessful. It later came to be called The Battle of Fort Duquesne.
Answer:
Running water and internal drainage systems were used to make them more safe and more sanitary to live in. The workers wages were also increased and workers could find jobs in the city.
Texas was annexed in 1845, and Oregon was Spain's territory.
