Water's unique property is best described as:

• A. Odorless, colorless, expands when frozen.
• B. Has a strong metallic taste.
• C. Expands when heated.
• D. Never changes volume with temperature.

Answer: (A)

Water’s behavior highlights a density anomaly: it is colorless and odorless, and it expands when it freezes. The hydrogen-bonded structure in ice forms a open lattice that keeps molecules farther apart, making ice less dense than liquid water so it floats. Describing water as odorless and colorless and noting that it expands upon freezing captures this distinctive property. The other statements don’t fit: water is not known for a metallic taste, and while substances often change volume with temperature, water’s key unusual feature is its expansion when freezing, not expansion when heated; and it does change volume with temperature, so saying it never does would be inaccurate.