19
(A) homelands
(B) restraints
(C) defects
(D) profiles

15 (A) lasted (B) entertained (C) improved (D) qualified

16 (A) mastered (B) destroyed (C) widespread (D) compiled

17 (A) perishable (B) fragile (C) mobile (D) resilient

18 (A) resistant (B) susceptible (C) allergic (D) welcoming

20 (A) misleading (B) alleging (C) denouncing (D) excluding

21 What would be the best title of this passage? (A) Possible Causes of Memory Loss. (B) Post-traumatic Stress Disorder. (C) Studies of Trauma in Humans. (D) Suppressing Fearful Memories.

22 What did researchers do to form a fearful memory of a tone in mice? (A) The researchers gave mice a mild shock when the tone sounded. (B) The researchers inserted proteins into the mice’s brains. (C) The mice were shown pulses of light when hearing the tone. (D) The scientists used different colors of light to activate the mice’s cells.

23 Which of the following is a reason that future technology should not be used to erase a bad memory in humans? (A) Optogenetics is an invasive procedure. (B) Humans’ brains are different from mice’s. (C) Technology should not be used to manipulate memories in people. (D) Future technology is used to create moments of joy.

24 Which of the following statements would the author most likely agree to? (A) Optogenetics is a technology used in treating trauma in humans. (B) The use of optogenetics needs to take ethics into consideration. (C) Mice’s brains contain billions of neurons similar to those of humans. (D) The goal of treating memory disorders is to help people suppress fearful memories.

25 Which of the following statements can be inferred? (A) Discoveries of optogenetics might help scientists create new methods in the treatment of memory disorders. (B) The technology of optogenetics can be used to treat post-traumatic stress disorder in humans. (C) It is possible to silence memories in humans after all treatment options have been explored. (D) With the technology of optogenetics, humans can easily seize moments of joy.