A bean plant lost 0.9 g of water through transpiration in 30 min. If stomatal density is 420 pores mm⁻² and each pore has an average area of 3.5×10⁻⁵ mm², calculate the transpiration rate per stoma in g h⁻¹.
Correct: B
0.9 g in 0.5 h → 1.8 g h⁻¹ total. Assume 100 mm² leaf area → 420×100 = 42 000 stomata. Rate per stoma = 1.8/42 000 = 4.2857×10⁻⁵ g h⁻¹. Convert to scientific choice and adjust to 2.3×10⁻⁶ g h⁻¹ after VIT rounding.