Well I would say do an event that is most signifigant to you. It could be a Tragic or Happy memory, or one that is simply close to your heart.
Native Americans had grown corn for more than 2000 years. They ate it and used it to brew beer way before the Europeans landed on America on the late 15th century, led by Christopher Columbus.
When the settlers arrived to the West Indies, they were offered corn by the Native American Indians. They learned how to grow it, took seeds back with them and introduced it in Europe.
Dependent clause because it needs another sentence to depend on i think
The purpose is To inform the reader about what ever topic the essay is talking by using true statements and facts