In 1804, Meriwether Lewis and William Clark began an expedition across the western United States, then known as the Louisiana Territory. The two men had met years earlier and established a long-lasting friendship. When Lewis was later a young captain in the army, he received a letter from President Thomas Jefferson offering him funding to explore the Western country. With Jefferson's permission, Lewis offered a partnership in the expedition to his friend Clark. When their journey had safely concluded 8,000 miles later, President Jefferson purchased the Louisiana Territory for fifteen million dollars.

The purpose of the passage is

1. to give the background to Lewis and Clark's westward expedition
2. to defend the purchase of the Louisiana Territory
3. to state a crucial decision made by Thomas Jefferson
4. to compare the skills of Lewis and Clark

Cancer occurs when cells in the body begin to divide abnormally and form more cells without control or order. There are some factors which are known to increase the risk of cancer. Smoking is the largest single cause of death from cancer in the United States. In addition, poor food choices increase cancer risk. Indeed, research shows that there is a definite link between the consumption of high-fat food and cancer.

From this passage, we can infer that

1. a low-fat diet can reduce the risk of cancer X
2. smoking usually causes cells to divide abnormally
3. the consumption of high-fat food has increased in recent years
4. most cancer sufferers have made poor food choices