5. Which stage of the cell cycle is the longest? 6. Why are onion root tips a good choice for viewing cells in different stages of the cell cycle?
7. Are there any mammalian cells that would be a good source for dividing cells? What types of cells
would most likely NOT have cells undergoing division?

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.