GRE Reading Comprehension: ETS-GRE阅读ETS - DQ6KD62593LSW1947

It can be inferred from the passage that which one of the following experimental results would suggest that bacteria detect changes in the concentration of an attractant by measuring its concentration in front and back of the cell body simultaneously? A. When suddenly transferred from a medium in which the concentration of an attractant was uniformly low to one in which the concentration was uniformly high, the tendency of the bacteria to tumble and undergo random changes in direction increased. B. When suddenly transferred from a medium in which the concentration of an attractant was uniformly low to one in which the concentration was uniformly high, the bacteria's exhibited no change in the pattern of their motion. C. When suddenly transferred from a medium in which the concentration of an attractant was uniformly low to one in which the concentration was uniformly high, the bacteria's movement was characterized by a complete absence of tumbling. D. When placed in a medium in which the concentration of an attractant was in some areas low and in others high, the bacteria exhibited an increased tendency to tumble in those areas where the concentration of the attractant was high. E. When suddenly transferred from a medium in which the concentration of an attractant was uniformly low to one that was completely free of attractants, the bacteria exhibited a tendency to suppress tumbling and move in longer, straighter lines.