What was the impact of the development of cities along the Silk Road?

The guards at the royal palace in london stand at attention while on duty. on a very hot day, it is not unusual for one (or more) to become light headed and faint. explain this phenomenon

In e. c. tolman's experiment, some rats were trained to run through mazes for standard food goals, while other rats were allowed to explore the mazes for 10 days without food goals or other rewards. later, when food rewards were placed in a box at the far end of the maze, the previously unrewarded rats reached the food box as quickly as the rewarded rats after only one or two trials. this experiment demonstrated that the rats had the ability to form of their surroundings.

The pka of three different c―h bonds is given below. explain the observed trend in pka. select the single best answer.