Which statements are true about all the natural chemical cycles?

-each cycle can operate and balance itself

-each cycle affects other cycles

-natural earth cycles cannot be disturbed

-human activity has upset cycles in local areas

-all the natural cycles work together to support life

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