Waec Model Questions Vol1 2019 Biology Question 40

Practice objective / multiple choice question 40 from the 2019 Waec Model Questions Vol1 Biology examination.

Waec Model Questions Vol1 2019 Biology Objective / Multiple Choice Hard Difficulty
Question 40 WAEC_MODEL_QUESTIONS_VOL1 • 2019 • BIOLOGY • objective

Two types of leaf are compared for water‑loss adaptation in a desert plant. Type A (broad leaf): surface area = 50 cm², thickness = 0.2 cm, stomatal density = 200 stomata·mm⁻². Type B (needle leaf): surface area = 5 cm², thickness = 0.5 cm, stomatal density = 50 stomata·mm⁻². Each stomata loses 0.05 µL of water per hour. Assume total water loss is proportional to the total number of stomata and inversely proportional to leaf thickness. Calculate the water loss per hour for each leaf type and state which leaf shows the better adaptation for minimizing water loss.

Answer Options

A. Type B (needle leaf) loses 2.5 mL·h⁻¹, which is far less than the 25 mL·h⁻¹ loss of Type A; therefore the needle leaf is the better adaptation.
B. Type B (needle leaf) loses 0.25 mL·h⁻¹, which is far less than the 250 mL·h⁻¹ loss of Type A; therefore the needle leaf is the better adaptation.
Correct Answer C. Type B (needle leaf) loses 2.5 mL·h⁻¹, which is far less than the 250 mL·h⁻¹ loss of Type A; therefore the needle leaf is the better adaptation.
D. Type B (needle leaf) loses 25 mL·h⁻¹, which is far less than the 250 mL·h⁻¹ loss of Type A; therefore the needle leaf is the better adaptation.
Correct Answer
C
Correct Option:
Type B (needle leaf) loses 2.5 mL·h⁻¹, which is far less than the 250 mL·h⁻¹ loss of Type A; therefore the needle leaf is the better adaptation.

About This Question

This is Waec Model Questions Vol1 2019 Biology Question 40. It is one of the objective questions from the 2019 Waec Model Questions Vol1 Biology examination.

Difficulty level: Hard .

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