Which of the following statements about the atmosphere is correct? 1. Troposphere is the lowest layer of the atmosphere. 2. Ionosphere lies above the mesosphere.

• Statement 1 is Correct: The Troposphere is the lowest layer of Earth's atmosphere. It contains roughly 75-80% of the atmosphere's mass and almost all water vapor. All weather phenomena (clouds, rain, etc.) occur here. • Statement 2 is Correct: The Ionosphere is a part of the upper atmosphere (specifically within the Thermosphere) that lies above the mesosphere. It is characterized by high concentrations of ions and free electrons and facilitates long-distance radio communication.