If the hypothesis stated at the end of the passage is true, it can be inferred that the crystallin proteins in the lenses of people with cataracts _______.

单项选择题Apples are used _______.

单项选择题Which of the following would be the best title for the passage

单项选择题The author has the approach of a (n) _______.

单项选择题The underlined term natural law as it appears in the middle of the second paragraph refers to _______.

单项选择题The writer is probably _______.