What is the primary composition of sweat?

• A. Water, salts, and waste products
• B. Protein and lipids
• C. Carbohydrates and calcium
• D. Urea and ammonia

Answer: (A)

The primary composition of sweat is water, salts, and waste products, which reflects the body's mechanisms for thermoregulation and waste elimination.

Sweat is approximately 99% water, which serves as the main solvent. This high water content allows for effective cooling of the body through evaporation. Salts, particularly sodium chloride, are present in smaller amounts and help maintain the body's electrolyte balance during sweating, which can occur during physical activity or in hot environments. Additionally, sweat contains mild amounts of waste products, including urea and lactate, which are excreted by the body to help regulate its internal environment and maintain homeostasis.

The other options, while they contain substances found in the body, do not accurately reflect the primary components of sweat. For example, protein and lipids are not significant constituents of sweat, and carbohydrates and calcium do not play a role in the composition of sweat. Similarly, while urea and ammonia may be components of sweat in small amounts, they are not the primary ingredients and are overshadowed by the larger quantities of water and salts.