A) 40%
B) 15%
C) 20%
D) 70%
E) 10%

A) the ECF and ICF have the same composition.
B) the plasma and the interstitial fluid have similar composition.
C) the cellular proteins freely permeate into the ECF from ICF.
D) the concentration of sodium ions and potassium ions in ECF and ICF is the same.
E) all these.

A) In the ECF, Na+ is accompanied primarily by Cl^- and to a lesser extent by HCO₃^-.
B) In the ICF K+ is accompanied by PO₄^3-.
C) In most organisms Na⁺ is the primary ion in the ICF.
D) A fluid compartment found in all animals is produced by the digestive tract.
E) All plasma constituents except proteins are freely exchanged between plasma and interstitial fluid.