the slope of this graph is zero from t = 3 seconds to t = 7 seconds. how does the distance change over this time?
a. the distance remains zero.
b. the distance does not change.
c. the distance decreases from 2.5 meters to zero meters.
d. the distance changes from three meters to seven meters.

d

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.

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.