What is the significance of checkpoints within the cell cycle?

Cell specialization occurs by the process ofa. reproductionb. differentiationc. maturationd. growth

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 direct energy source that drives atp synthesis during respiratory oxidative phosphorylation is