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CPCS: CERTIFIED PROFESSIONAL CROP SCIENTIST EXAM 2026/2027 | 100%
VERIFIED EXAM QUESTIONS & ANSWERS | PASS GUARANTEE
Question 1 [Soil Science]
Which of the following best describes cation exchange capacity (CEC) in soils?
A. The ability of soil to absorb and hold water molecules in pore spaces
B. The total capacity of a soil to retain exchangeable cations such as Ca2+,
Mg2+, and K+
C. The rate at which soil releases carbon dioxide during microbial respiration
D. The measure of soil compaction expressed as mass per unit volume
✔ Correct Answer: B
Correct Answer: B. CEC refers to the soil's capacity to hold positively charged
ions (cations) on its surface, which prevents them from leaching and keeps them
available for plant uptake. Option A describes water-holding capacity, not CEC.
Option C describes soil respiration, a biological process. Option D describes bulk
density, which is a physical soil property.
Question 2 [Plant Physiology]
Which photosynthetic pathway is most efficient under hot, dry, and high-light
conditions, and why?
A. C3 pathway, because it uses Rubisco to directly fix CO2 without any
additional energy cost
B. CAM pathway, because it fixes carbon during the day when temperatures are
highest
C. C4 pathway, because it concentrates CO2 around Rubisco, minimising
photorespiration
D. C3 pathway, because it produces more ATP per molecule of CO2 fixed than
C4 plants
Certified Professional Crop Scientist (CPCS) — Examination Practice Paper
CPCS: CERTIFIED PROFESSIONAL CROP SCIENTIST EXAM 2026/2027 | 100%
VERIFIED EXAM QUESTIONS & ANSWERS | PASS GUARANTEE
Question 1 [Soil Science]
Which of the following best describes cation exchange capacity (CEC) in soils?
A. The ability of soil to absorb and hold water molecules in pore spaces
B. The total capacity of a soil to retain exchangeable cations such as Ca2+,
Mg2+, and K+
C. The rate at which soil releases carbon dioxide during microbial respiration
D. The measure of soil compaction expressed as mass per unit volume
✔ Correct Answer: B
Correct Answer: B. CEC refers to the soil's capacity to hold positively charged
ions (cations) on its surface, which prevents them from leaching and keeps them
available for plant uptake. Option A describes water-holding capacity, not CEC.
Option C describes soil respiration, a biological process. Option D describes bulk
density, which is a physical soil property.
Question 2 [Plant Physiology]
Which photosynthetic pathway is most efficient under hot, dry, and high-light
conditions, and why?
A. C3 pathway, because it uses Rubisco to directly fix CO2 without any
additional energy cost
B. CAM pathway, because it fixes carbon during the day when temperatures are
highest
C. C4 pathway, because it concentrates CO2 around Rubisco, minimising
photorespiration
D. C3 pathway, because it produces more ATP per molecule of CO2 fixed than
C4 plants
Certified Professional Crop Scientist (CPCS) — Examination Practice Paper
