A New Discovery about the Brain

Reese needs to improve the introduction of his essay. Which sentence should be added before sentence 1 to create a more effective introduction for his essay?

• There are so many mysteries about the human body that you would never believe it.

• The brain is like the body’s big jigsaw puzzle.

• Over the past centuries, many of the mysteries of the human body have been explained by science.

• Scientists are determined to find out all the facts that can help them understand our world.

Where should Reese insert this idea?

• After sentence 4

• After sentence 5

• After sentence 6

• Reese should not insert this idea.

Reese needs a better transition between the second paragraph (sentences 4–8) and the third paragraph (sentences 9–14). Which sentence should replace sentence 9 to create a more effective transition?

• Until recently, scientists could not determine how the brain is able to rid itself of waste because the lymphatic system does not include the brain.

• Scientists researched the brain for years before finally making a breakthrough.

• No one knew how the brain was able to perform some functions.

• The lymphatic system does not include the brain, so everyone always wondered about that.

Reese wants to improve the clarity of sentence 12. How should sentence 12 be revised?

• Running along the brain’s blood vessels, the team determined is a fluid that carries waste away from the brain.

• The team determined that fluid running along the brain’s blood vessels carries waste away from the brain.

• Waste by a fluid that is running along the brain’s blood vessels is carried away from the brain, the team determined.

• Along the side of the brain’s blood vessels is a fluid, the team determined, and this carries away from the brain waste.

Which sentence should Reese add after sentence 18 to provide additional support for the inference in sentence 19?

• It would be a good idea to get rid of these bad proteins.

• Another type of protein is important to building strong muscles.

• Alzheimer’s is a disease that is heavily researched.

• Some of these same proteins appear in the waste products of brain cells.