The growing shoot tips of a plant are removed and set onto small blocks of jelly that contain no auxin. In some of the jelly blocks, small pieces of transparent but impermeable glass are inserted, as shown in diagram X. In diagram Y, some of the shoot tips are separated by pieces of transparent impermeable glass. The tips are then left on the small jelly blocks while light shines from only one side. After 12 hours, the number of arbitrary units of auxin in each jelly block is measured and the means, shown in the diagrams, are worked out. A student recorded these conclusions from the results. 1. Auxin moves downwards out of the shoot tip. 2. The distribution of auxin in a shoot tip is affected by light intensity. 3. Some auxin is destroyed by light. 4. Auxin moves from areas of more light to areas of less light. Which of the student’s conclusions are correct?
- A1, 2, 3 and 4
- B1, 2 and 4 only
- C1 and 3 only
- D2, 3 and 4 only