Which of the following is true of modern cell theory?
(a)as technology improves, so will our understanding of cells.
(b)early cell theory has turned out to be incorrect.
(c)multi-celled organisms are the focus of most modern discoveries.
(d) scientists have learned all they can about cells at this point.

idk

explanation:

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.