A recent study shows that by the end of this century, the average temperature of the earth will be 3 㠃 higher than it is now. This prediction is based on the phenomenon of rising global temperatures and the greenhouse effect in recent years. The greenhouse effect, in physics, refers to perspective The enclosed space of the sunlight has a thermal insulation effect due to the lack of heat exchange with the outside world. Carbon dioxide in the atmosphere is the main greenhouse gas, which can reduce the loss of surface heat to space and maintain a certain amount of heat in the atmosphere. Based on the above, what is the following explanation of the concept of the "greenhouse effect"? ['This refers to the effect of the lack of heat exchange with the outside world such as carbon dioxide and other greenhouse gases, which has caused a corresponding increase in surface temperature.', 'Refers to the effect of increasing the carbon dioxide content in the enclosed space that receives sunlight, which can increase the surface temperature.', 'This refers to a kind of thermal insulation effect in a certain enclosed space capable of receiving sunlight due to lack of heat exchange with the outside, such as convection.', 'This refers to the main greenhouse gas in the atmosphere, which reduces the heat loss from the surface to space, and produces a thermal insulation effect in a specific confined space.']