Which molecule is the most important constituent of all body fluids?

• A. Sodium chloride (NaCl)
• B. Urea (CH\(_4\)N\(_2\)O)
• C. Water (H\(_2\)O)
• D. Glucose (C\(_6\)H\(_{12}\)O\(_6\))

Answer: (C)

Verified step by step guidance

1. Understand the question: The problem is asking which molecule is the most important constituent of all body fluids. This requires knowledge of the composition and function of body fluids in biochemistry.
2. Recall the primary component of body fluids: Body fluids, such as blood, lymph, and intracellular fluid, are primarily composed of water (H\(_2\)O), which serves as a solvent for biochemical reactions and transport of molecules.
3. Analyze the options: Sodium chloride (NaCl) is an important electrolyte, urea (CH\(_4\)N\(_2\)O) is a waste product, and glucose (C\(_6\)H\(_{12}\)O\(_6\)) is a key energy source. However, none of these are as abundant or universally essential as water.
4. Consider the role of water: Water is critical for maintaining homeostasis, regulating temperature, and facilitating biochemical reactions. It makes up about 60% of the human body and is the primary medium for all cellular processes.
5. Conclude the answer: Based on the above reasoning, water (H\(_2\)O) is the most important constituent of all body fluids.