Advanced Science Primary 5 Systems

A ring of bark was removed from a plant stem at point X, as shown in the diagram. After one week, a swelling was observed above point X. Which tubes were removed?

A Neither tubes were removed
B Only food-carrying tubes
C Both water and food-carrying tubes
D Only water-carrying tubes
Show Worked Solution

Worked Solution

Step 1: Food is made in leaves and moves DOWN. Step 2: Water is absorbed by roots and moves UP. Step 3: Swelling above X means food is trapped and cannot move down. Step 4: This indicates food-carrying tubes (phloem) were removed while water tubes (xylem) remained.

Correct answer: Only food-carrying tubes

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