4. Which of the following is an important characteristic of a scientific theory? a, proven by more than one scientist
b. unchanged by new evidence
c. accepted by the public
d. supported by much evidence

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.

thinking it would be d not too sure but i think it's right

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.