40. Which of the following is a major difference between hydroponics and aquaponics?
(A) In a hydroponics system, plant roots are exposed directly in water.
(B) In a hydroponics system, the water provides plants with rich nutrient.
(C) In an aquaponics system, plants are grown with their roots exposed to the air.
(D) In an aquaponics system, fertilizer from fish waste can nourish crops.
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統計: A(25), B(93), C(23), D(191), E(0) #3128968
統計: A(25), B(93), C(23), D(191), E(0) #3128968