Essential elements are
A. Only macronutrients
B. Only micronutrients
C. Both macro and micronutrients
D. C,H,O and N only

Hint: Some essentials elements are required in a larger amount than the other and these are the macronutrients. Those required in the fewer amounts are the micronutrients. All the elements are required in specific amounts.

Complete answer: The essential elements cannot synthesize in the body, for example, the elements like sodium, potassium, silicon, etc. The essential elements are those elements that need to be taken from the food or from other external mediums. The elements like oxygen, carbon, hydrogen, nitrogen, and also the sulfur are also known as the bulk elements or as the macro elements. In addition to these elements, sodium, magnesium, potassium, calcium, chlorine, and phosphorus are also present.
These six elements are known as microminerals.
Therefore, the correct answer is option C.
Additional information:
Any of a number of elements that are required for the living organisms to ensure normal growth, development, and maintenance is known as the essential elements. The elements found in organic compounds, plants, animals, and microorganisms all require a range of elements in inorganic forms in varying amounts, depending on the type of the organism. The major elements present in tissues in relatively large amounts are calcium, phosphorus, potassium, sodium, chlorine, sulphur, and magnesium.
The trace elements occur at much lower concentrations and therefore the requirements are much less. The most important elements are iron, manganese, zinc, copper, iodine, cobalt, selenium, molybdenum, chromium, and silicon. Each element may fulfill one or more of a variety of metabolic roles. The sodium, potassium, and chloride ions are the chief electrolytic components of the cells and body fluids and therefore determine their electrical and osmotic status. The elements like calcium, phosphorus, and magnesium are all present in the bone.

Note: The six most common elements in living things are carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulphur. The atoms of these elements combine and form thousands of large molecules. These large molecules maintain the structures of cells and carry out many processes that are very essential to daily life. The essential element is one that is required for life and whose absence results in death.