Pre AP Biology -ECO 1.2 Carbon and Nutrient Cycles- MCQ Exam Style Questions -New Syllabus
Pre AP Biology -ECO 1.2 Carbon and Nutrient Cycles- MCQ Exam Style Questions – New Syllabus 2025-2026
Pre AP Biology -ECO 1.2 Carbon and Nutrient Cycles- MCQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.
▶️ Answer/Explanation
Hydroponic culture is a method of growing plants in a nutrient-rich water solution instead of soil.
This technique allows researchers to determine which mineral elements are essential for plant growth.
By omitting specific nutrients, such as $Mg^{2+}$ or $N$, scientists can observe specific deficiency symptoms.
It requires precise control over the concentration and combination of dissolved inorganic salts.
Unlike options b and c, it focuses on mineral nutrition rather than light or temperature.
Unlike option d, it explicitly eliminates the use of soil to avoid unknown nutrient variables.
▶️ Answer/Explanation
The correct option is c.
Fertilizer labels use the $N-P-K$ rating system standing for Nitrogen, Phosphorus, and Potassium.
The first number represents $15\%$ Nitrogen ($N$) for leaf growth.
The second number represents $30\%$ Phosphorus ($P$, expressed as $P_2O_5$) for root and flower development.
The third number represents $15\%$ Potassium ($K$, expressed as $K_2O$) for overall plant health.
These three elements are the primary macronutrients required by plants.
Other elements like iron or sulfur are micronutrients and are not part of the standard $3$-number label.
▶️ Answer/Explanation
The correct answer is d. nitrogen.
Carnivorous plants typically grow in nutrient-poor environments, such as bogs or acidic swamps.
In these habitats, the soil is extremely deficient in available $\text{nitrogen}$.
While these plants still perform photosynthesis to gain carbon, they “eat” insects to supplement their mineral intake.
By digesting animal proteins, the plants extract essential $\text{nitrogen}$ compounds needed for growth.
This adaptation allows them to thrive where other plant species cannot survive due to soil limitations.