Passage Three
Question 18 to 20 are based on the passage you have just heard.
18. A) How animals survive harsh conditions in the wild.
B) How animals alter colors to match their surroundings.
C) How animals protect themselves against predators.
　　D) How animals learn to disguise themselves effectively.
19. A) Its enormous size.
　　B) Its plant-like appearance.
　　C) Its instantaneous response.
　　D) Its offensive smell.
20. A) It helps improve their safety.
　　B) It allows them to swim faster.
　　C) It helps them fight their predators.
　　D) It allows them to avoid twists and turns.