Gas → solid directly is called:

**The reasoning** When a substance changes **directly from gas to solid** without passing through the liquid state, this process is called **deposition**. Think of frost forming on a cold morning — water vapor in the air goes straight to ice crystals on surfaces, skipping the liquid water stage entirely. The principle here is understanding phase transitions: deposition is the reverse of sublimation (solid → gas). **Why the wrong options tempt you** - **Evaporation (A)** is liquid → gas, like water drying from clothes - **Condensation (B)** is gas → liquid, like water droplets forming on a cold bottle of Coke from the fridge - **Sublimation (C)** is the *opposite* direction: solid → gas directly (like camphor or dry ice disappearing without melting). This is the biggest trap because sublimation involves gas and solid, but in the wrong direction! **Quick takeaway** **Deposition = gas deposits as solid** (think frost on grass); sublimation goes the other way. Remember: "DEPosition = DEscending from gas DOWN to solid."