Help with biology question attached

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks

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

The cell membrane controls what enters and leaves the cell. which of the structures in the diagram below is the cell membrane? — f о