Minerals and Nutrients

Soil is the primary source of both macronutrients (nitrogen, phosphorus, potassium) and micronutrients (iron, zinc, copper) for plants. Air provides carbon dioxide and oxygen, while sunlight provides energy and water is a solvent, but soil contains the mineral nutrients essential for plant growth.

Calcium, phosphorus, and sulfur are all macronutrients required by plants in relatively large amounts. Iron is a micronutrient, needed in much smaller quantities, making it the correct answer as the exception.

Fertilizers primarily supply three macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K) - collectively known as NPK. Sodium (Na) is not a primary plant nutrient and is not a major component of commercial fertilizers. While plants need tiny amounts of sodium, it's not supplied through fertilization as it can be toxic at higher levels and is rarely deficient in soils.

Spirulina (blue-green algae) is a very high source of protein, minerals, vitamins, beneficial pigments and antioxidants that can be consumed by humans and other animals.

Chlorophyll is the chief component of algae. With the help of chlorophyll, the algae prepare their own food.

Potassium and sodium are two essential minerals used to regulate and maintain the cardiovascular system. Sodium is required for the nervous system to effectively communicate with and coordinate various parts of the body. If sodium levels are inadequate for neuronal function, then a muscle cell will fail to function properly.

Macronutrients are nutrients required in large amounts: carbohydrates, proteins, and fats. Minerals like Ca (calcium), P (phosphorus), and K (potassium) are macronutrients. Mn (manganese) is a micronutrient/trace mineral required only in small amounts, making it the correct answer.

Sulphur is a critical component of two proteinogenic amino acids: cysteine and methionine. These sulphur-containing amino acids are essential for protein synthesis. While sodium, iron, and potassium are vital minerals, they are not structural components of amino acids themselves.

Cell membranes are primarily composed of phospholipids (lipid bilayer) and membrane proteins. Proteins and lipids work together for membrane structure and function. While carbohydrates are present as glycoproteins/glycolipids, and fats/minerals have roles, proteins and lipids are the chief structural components.

Calcium, phosphorus, sodium, and magnesium are macrominerals required in substantial amounts (hundreds of milligrams to grams daily). Calcium and phosphorus are critical for bones, sodium for fluid balance, and magnesium for enzyme function. Options A, B, and D include trace minerals (molybdenum, zinc, manganese, cobalt, copper) which are needed in much smaller quantities.

Carbon is the most abundant element in plants by mass (about 45-50% of dry weight), as plants are primarily composed of carbon-based compounds like cellulose, lignin, and sugars. Nitrogen is important but less abundant (1-5%), while iron and manganese are micronutrients.

Macronutrients are elements plants need in large amounts. Primary macronutrients are N, P, K. Secondary macronutrients include Ca (calcium), Mg, and S. Manganese, chlorine, and copper are all micronutrients needed in trace amounts.

The four most abundant elements in living cells are Carbon, Hydrogen, Oxygen, and Nitrogen (CHON), which together make up about 96% of cellular mass. Phosphorus (P), Sulfur (S), Magnesium (Mg), and Calcium (Ca) are all present but less abundant.

Macronutrients are elements plants need in large quantities. Primary macronutrients are N, P, K. Secondary macronutrients include Ca (Calcium), Mg, and S. Molybdenum (Mo), Manganese (Mn), and Zinc (Zn) are all micronutrients needed only in trace amounts.