I wonder what part the "inside" is in the context? The glass lets in light from the sun. The light heats up the soil and plants. The glass does not let much of the heat escape. The air inside stays warm. I know that it's not important to tell whether it's adverb or adjective. I wonder what part the "inside" is in the context? If the word "inside" is adjective, I think it would be better to change the location of the word "inside" in front of "air." Is it right?