In this passage, Nick reflects on what the landscape must have looked like when the Dutch explorers arrived to the continent. He is looking at Gatsby's house, and at this point in the novel, we know that Nick believes that New York, as well as the people he has met, are vile, corrupt and greedy. He contrasts this view with that of the pristine continent on the arrival of the European settlers.
The phrase "fresh, green breast of the New World" presents a view that is "fresh." The land is new, but it is also fresh in the sense that it is not rotten. The land has not yet been "infected" with the corruption of modern times. Therefore, the phrase is intended to represent a time before America had become a land of greed and vice.
I don’t know I would look it up
Reaction times are reduced and ability to assess risk is also lowered
