Neco 2022 Biology Question 30

Two desert plant species differ in leaf adaptations. Species X has leaf area \(150\,\text{cm}^2\) and stomatal density \(300\,\text{stomata\,mm}^{-2}\); its cuticle thickness is \(0.5\,\mu\text{m}\). Species Y has leaf area \(120\,\text{cm}^2\), stomatal density \(200\,\text{stomata\,mm}^{-2}\) and cuticle thickness \(1.0\,\mu\text{m}\). Each stomatal pore loses water at a rate of \(0.05\,\mu\text{mol\,s}^{-1}\). Assume cuticular water loss is inversely proportional to cuticle thickness (effective loss = base loss ÷ thickness in µm).\n(a) Calculate the total water loss per leaf per second for each species.\n(b) Which adaptation - lower stomatal density or thicker cuticle - contributes more to the reduced water loss observed in Species Y compared with Species X? Provide a brief quantitative justification.