Igcse Model Questions Vol1 2018 Biology Question 9

Practice objective / multiple choice question 9 from the 2018 Igcse Model Questions Vol1 Biology examination.

Igcse Model Questions Vol1 2018 Biology Objective / Multiple Choice Hard Difficulty
Question 9 IGCSE_MODEL_QUESTIONS_VOL1 • 2018 • BIOLOGY • objective

A desert plant leaf has an area of \(0.02\ \text{m}^2\) and a stomatal density of \(150\ \text{stomata mm}^{-2}\). During peak heat only 20 % of the stomata open, each losing water at a rate of \(0.5\ \mu\text{L h}^{-1}\). The plant stores \(0.5\ \text{kg}\) of water and can lose at most 5 % of this store per hour. (a) Calculate the total water loss per hour (in \(\mu\text{L h}^{-1}\) and in kg h⁻¹). (b) What maximum percentage of the total stomata can remain open without exceeding the 5 % loss limit?

Answer Options

A. a) 300 000 µL h⁻¹ (0.30 kg h⁻¹); b) ≈5 % of stomata can stay open
Correct Answer B. a) 300 000 µL h⁻¹ (0.30 kg h⁻¹); b) ≈1.7 % of stomata can stay open
C. a) 450 000 µL h⁻¹ (0.45 kg h⁻¹); b) ≈0.9 % of stomata can stay open
D. a) 150 000 µL h⁻¹ (0.15 kg h⁻¹); b) ≈3.4 % of stomata can stay open
Correct Answer
B
Correct Option:
a) 300 000 µL h⁻¹ (0.30 kg h⁻¹); b) ≈1.7 % of stomata can stay open

About This Question

This is Igcse Model Questions Vol1 2018 Biology Question 9. It is one of the objective questions from the 2018 Igcse Model Questions Vol1 Biology examination.

Difficulty level: Hard .

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