Which three primary nutrients are necessary for plant growth?

The correct answer highlights the essential building blocks for plant growth, which are carbon, hydrogen, and oxygen. These three elements are pivotal because they form the foundational components of plant cells and are integral in processes such as photosynthesis and respiration.

Carbon is captured from the atmosphere in the form of carbon dioxide during photosynthesis. Plants utilize this carbon to create sugars and other organic compounds, driving their growth. Hydrogen, primarily absorbed through water, forms part of plant structures and is vital in biochemical processes. Oxygen, also obtained from water and used during photosynthesis, is essential for respiration and energy production in plants.

While nitrogen, phosphorus, and potassium are also critical nutrients known as macronutrients that contribute to various functions such as photosynthesis, energy transfer, and overall plant health, the question emphasizes the primary nutrients that constitute a plant's core composition. The emphasis on carbon, hydrogen, and oxygen reflects their fundamental role in structuring plant matter and facilitating life-sustaining processes.