Final answer:
option a.Sodium is the electrolyte mainly responsible for osmotic pressure due to its significant presence in the extracellular fluid and its role in fluid balance and osmotic gradients.
Step-by-step explanation:
The electrolyte primarily responsible for osmotic pressure is sodium (A). Sodium is the major cation found in the extracellular fluid and is accountable for about half of the osmotic pressure gradient existing between cells and their surrounding environment. It also plays a significant role in regulating blood pressure and is chiefly excreted by the kidneys. Although chloride contributes to osmotic balance by following the paths of sodium ions and is the most abundant extracellular anion, sodium's role in osmolarity is more pronounced, rendering it crucial for maintaining the proper balance and distribution of body fluids.
Chloride is the electrolyte primarily responsible for osmotic pressure in the body. It is the major contributor to the osmotic pressure gradient between the intracellular and extracellular fluid, which helps maintain proper hydration. Chloride functions to balance cations in the extracellular fluid, ensuring electrical neutrality. The secretion and reabsorption of chloride ions in the renal system closely follow the paths of sodium ions.