What are the 2 elements involved in the sun's production of energy?

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

Aragonite shells of clams, snails, or scleractinian corals may be preserved unaltered in cenozoic deposits, but they are generally dissolved or recrystallized in older deposits. true or false

Northern switzerland has a fairly cold climate caused by sea winds from the atlantic ocean but souther switzerland tends to be much warmer and sunnier, what could cause this difference?