Standard Science Primary 5 Systems

Ravi coated the underside of all the leaves of a healthy plant with a thick layer of oil. After a few days, the plant died. Why?

A The oil prevented the plant from absorbing sunlight.
B The oil blocked the stomata, preventing gas exchange.
C The oil poisoned the plant.
D The oil stopped the plant from taking in water through its leaves.
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Worked Solution

Step 1: Most stomata are located on the underside of leaves. Step 2: Stomata are used for taking in CO2 and releasing O2/water vapour. Step 3: Oil blocks these openings, stopping photosynthesis and respiration.

Correct answer: The oil blocked the stomata, preventing gas exchange.

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