Is rock a solid liquid or gas?

Which sentence from the story is an example of conflict? “here were many men, and countless dogs, and buck found them all at work.” “buck had been purposely placed between dave and sol-leks so that he might receive instruction.” “by afternoon, perrault, who was in a hurry to be on the trail with his despatches, returned with two more dogs.” “that night buck faced the great problem of sleeping.”

What is the meaning of the word checking as it is used in this sentence from the second paragraph of the passage?

To meet the needs of commuters in the industrial age, city planners implemented the use of phonographs. provided more horses and carriages. borrowed technology from railroads. constructed new telephone lines.