Some societies, like Canada and the United States, have changed rapidly while other places, like some African nations, have seen far less change. Why are these African nations MOST likely slower to change?
ОА
African nations are generally very reluctant to adopt new policies,
ОВ.
African nations often do not have access to the resources of industrial nations.
OC. Western nations tend to keep innovations to themselves and not spread culture.
OD. Most African nations do not have the natural resources they need to industrialize.

You need to be more specific.  i really don't know what a "motion map" is.you can draw a graph of an object's position, distance, displacement, speed,velocity, or acceleration versus time, or you can draw a graph of the object's x-position versus its y-position and not give any information about time at all.if the graph presents position or displacement against time,  then constant velocity is a straight line . . i.e. a line that has  constant slope.if the graph shows speed against time, then constant velocityis a horizontal piece of line.if the graph shows acceleration against time, then constant  velocity is a piece of line that lies on the x-axis . . it's value is zero. 

We can infer that star y is closer but other factors must be considered including the heat of the star, the mass, and the brightness of the star. even though star x seems dimmer it may just be less bright or contain less heat.