The Precambrian eon is separated from the Phanerozoic eon in the fossil record because of poorer record of fossils than that of the succeeding Phanerozoic eon.This is because many Precambrian rocks have been heavily metamorphosed,obscuring their origins,while others have been destroyed by erosion,or remain deeply buried beneath Phanerozoic strata.The Phanerozoic Eon covers 541 years to the present while Precambrian Eon covers 4.6 billion years.
D. They wanted to break Muslim & Italian control on trade.
The correct answer is C. The closing of the western frontier.
In his 1893 published paper, The Significance of the Frontier in American History, Turner stated that while it was technically true that the frontier was closed, it was the frontier life that shaped the success of the United States. His idea, which was summarized in his frontier thesis, traced the development of the United States using the settlement of the West as a measure. He argued that early settlers were essentially Europeans; they had European values and European character, but because of the frontier experience, they had to adapt, resulting in their placing a greater value on things like ingenuity, democracy and individualism. Furthermore, it was these experiences of living out in the frontier that led to settlers becoming distrustful of authority, less artistic, and more violent.
The Lusitania. It was torpedoed without any warning off the south coast of Ireland. 1,198 out of the 1,959 passengers/crew drowned.