Which statement is most helpful in identifying frost?

Correct answer: White ice crystals appear on the surface

Correct answer: A. Frost is a deposit of ice crystals on exposed surfaces when the surface and nearby conditions are cold enough. Its most useful visible identifying feature is a white, crystalline coating on grass, leaves, soil, roofs, or other objects. Option A is therefore correct because it describes the appearance and location of frost. Option B refers to dust, not condensed or deposited water. Option C is unrelated: frost is not defined by reduced visibility or by occurring only near the sea. Option D describes liquid water that is warm, which is opposite to the cold condition associated with frost. A useful distinction is that fog and mist are made of droplets suspended in air, whereas frost is visible on a surface as ice crystals. Dew is also a surface deposit, but it is normally liquid water; frost is frozen and crystalline. Do not choose frost merely because the morning is cold—the identifying evidence is the visible surface ice. Memory cue: “Frost forms a frozen white coat.”