Of all the water in the human body, approximately what fraction is intracellular fluid (ICF)?

1. Total body water is divided between the intracellular fluid (ICF) and extracellular fluid (ECF) compartments. 2. The ICF is the larger of the two compartments. 3. The ICF as about 60 percent of total body water, roughly 25 litres in an average adult male. 4. 33 percent is closer to the ECF share, and 20/80 percent do not match either compartment, so they are ruled out. 5. Therefore 60 percent is correct. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 26 "Fluid, Electrolyte, and Acid-Base Balance", p.1250 §Intracellular Fluid_