The document discusses greenhouses and the greenhouse effect. It defines a greenhouse as a structure made of glass or plastic used to grow plants at a higher internal temperature. It then provides background on the discovery and study of the greenhouse effect, noting that greenhouse gases like water vapor, carbon dioxide, methane, and ozone trap heat in Earth's atmosphere. The document also states that human activities like increased carbon dioxide emissions have strengthened the greenhouse effect, contributing to climate change. Finally, it mentions that other planets and celestial bodies exhibit similar greenhouse effects.