The tips of growing shoots of a plant are cut off and placed on small blocks of jelly which contain no auxin. Small pieces of impermeable clear glass are placed in some of the jelly blocks, as shown in diagram X. Some of the shoot tips are divided by impermeable clear glass pieces, as shown in diagram Y. The tips are left on the small blocks of jelly with light coming from one side only. After 12 hours, the number of arbitrary units of auxin is measured in each of the jelly blocks and the means, shown in the diagrams, are calculated. [Figure 27.1] A student wrote down some 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?

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