CAPE Biology Unit 2 · May/June 2026 · Paper 2 · Question 2(c)(i)
The root endodermis regulates water and nutrient uptake, and uses the Casparian strip, which is composed of suberin and lignin, to block harmful substances. Recent research shows that suberin levels adjust in response to environmental stresses such as salinity and nutrient availability. The results of the research that was undertaken are shown in Figures 7 and 8.
Outline ONE characteristic of the Casparian strip that allows it to control the movement of water and ions into the xylem of a plant.
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