Atmospheric carbon dioxide produces a so-called "greenhouse effect" by trapping heat near earth's surface. what human activities might tend to increase the greenhouse effect?

Which statement correctly describes other ways in which nebulae and stars are different? a. a star always has a higher density than a nebula. b. stars can form inside a nebula but a nebula can never be produced by any star. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star. reset submit