複選題18. Which of the following statements is true? (A) In Crassulacean acid metabolism (CAM) plants, carbon fixation and the Calvin cycle occur in the same cells at different times. The Calvin cycle of CAM plants occurs during the night, so that the Calvin cycle is also named the dark reaction. (B) Pineapples are CAM plants. (C) For C4 plants, the Calvin cycle is mainly carried out in the mesophyll cells. (D) C4 plants are less resistant to drought than C3 plants. (E) Photorespiration occurs when stomata of C3 plants are fully open during the day.