Answer:
1) The Greenhouse Effect works When the Sun's energy reaches the Earth's atmosphere, Some of it is reflected in space, and the rest is absorbed and re-radiated by the greenhouse gases.
2) The greenhouse effect is the trapping of heat under the atmosphere, which is a natural effect caused by greenhouse gases. However, when greenhouse gas concentrations are too high, they trap too much heat and increase the temperature on Earth, causing the enhanced greenhouse effect.