be safe for other animals.

　　"These compounds are really cool because they are not proteins-they are other types of molecules that nonetheless can do at least part of what natural antifreeze proteins do, "says Clara do Amaral, a biologist at Mount St. Joseph University, who was not involved in the research. Gibson's antifreeze compounds will still need to be tested in humans, however, and may be only part of a solution. "We don't have the whole picture yet, "do Amaral adds. "It's not just one magical compound that helps freeze-tolerant organisms survive. It's a whole suite of adaptations.

6. What will happen if organs are kept for a long time in temperatures below zero?

A. They will have ice crystal formation inside.

B. They will not suffer permanent damage.

C. They will have longer shelf life.

D. They will be fit for transplantation.

7. What can we learn about natural antifreeze proteins?

A. They look like Gibson's antifreeze compounds.

B. They are composed of antifreeze molecules harmless to other species.

C. They are spiral-shaped and have iron atoms at their centers.

D. They can be found in organisms living in freezing cold weather.

8. How are antifreeze molecules prevented from ice crystals?

A. By creating compounds both water-repellent and water-loving.

B. By extracting the proteins from some hardy animals.

C. By making synthetic alternatives like antifreeze proteins.

D. By copying spiral-shaped molecules mostly water-resistant.

9. What's the main idea of the passage?

A. Push-pull chaos might prevent water molecules from turning into ice.

B. The final solution to preserving donor organs has been found recently.

C. Chemicals inspired by Arctic animals could lengthen organs' shelf life.

D. Gibson's antifreeze compounds can do what natural antifreeze proteins do.