🔍 Key Concepts

• Layers of the atmosphere and which one is closest to the Earth’s surface • Where most weather (clouds, storms, precipitation) actually occurs • How air density and pressure change with altitude in different layers

💭 Think About

• First, recall the main layers of the atmosphere in order starting from the Earth’s surface upward—identify the first two or three and their key traits. • Think about which layer has the highest air density and pressure, because that’s where most of the atmosphere’s mass will be located. • Match the description “clouds, storms, precipitation, changing weather conditions” to the layer you’ve learned is associated with day‑to‑day weather, not just ozone or boundary regions.

✅ Before You Answer

• Verify which layer directly touches the Earth’s surface and extends upward for only a few miles/kilometers. • Check which option names a layer versus which options name boundary regions (interfaces) between layers. • Confirm from your notes which layer is specifically taught as containing most of the atmospheric mass and nearly all weather phenomena.