Standard Science Primary 5 Systems

Stan removed an outer ring of a plant stem, removing the food-carrying tubes but leaving the water-carrying tubes intact. A week later, he noticed a swelling just ABOVE the cut. What caused the swelling?

A Water absorbed by the roots accumulated above the cut.
B Mineral salts could not travel down to the roots.
C The plant was growing a new branch.
D Food made by the leaves accumulated above the cut.
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Worked Solution

Step 1: Leaves make food during photosynthesis. Step 2: Food-carrying tubes (phloem) transport this food downwards to other parts of the plant. Step 3: By removing the outer ring, the downward path is broken. Step 4: Food accumulates just above the cut, causing it to swell.

Correct answer: Food made by the leaves accumulated above the cut.

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