From which layer of atmosphere radio and microwaves are reflected back? 

Answer

**Step-by-Step Solution:**

1. **Understanding the Atmosphere Layers**: The Earth's atmosphere consists of several layers, including the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Each layer has different characteristics and functions.

2. **Identifying the Relevant Layer for Radio and Microwaves**: Among these layers, we need to identify which one is responsible for reflecting radio and microwaves back to Earth.

3. **Defining the Ionosphere**: The ionosphere is a part of the thermosphere and is characterized by the presence of ionized gases. This layer is crucial for radio communication as it reflects certain frequencies of radio waves.

4. **Mechanism of Reflection**: When radio waves are transmitted, they can reach the ionosphere, where they encounter ionized particles. These particles reflect the waves back towards the Earth, allowing for long-distance communication.

5. **Conclusion**: Therefore, the layer of the atmosphere that reflects radio and microwaves back to Earth is the **ionosphere**.

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