Answer :

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1. A greenhouse gas is:

- Gases that trap heat in the atmosphere.

Greenhouse gases are gases in Earth's atmosphere that trap heat. They allow sunlight to enter the atmosphere but prevent some of the heat that the sunlight brings from escaping back into space. This process is known as the greenhouse effect, which is essential for maintaining Earth's temperature suitable for life. Examples of greenhouse gases include carbon dioxide (CO2), methane (CH4), and water vapor.

I hope this explanation helps you understand the concept of greenhouse gases better! If you have any more questions or need further clarification, feel free to ask.