The correct answer for the question that is being presented above is this one: "B. building of the transcontinental railroad --> disappearance of the frontier." The pair of events that did the first event most directly influence the second is the building of the transcontinental railroad --> disappearance of the frontier.
Answer:
1 hr on problems and 3 reading
Explanation:
1 hr on problems bc he's able to finish 40 problems which is better than reading for 1 hr since the teacher said reading for 1 hr is equivalent to solving 35 problems. in the 2nd, 3rd and 4th hours he solves less than 35 problems each hour so it's better to just read for an hour.
P represents heating and Q represent cooling.
this is because when you start from a liquid and turn to a gas the particles move faster making them farther apart, causing a gas. the opposite happens when you go from a liquid to a solid. the partials move closer together causing a solid to form. :)
