When heavy rain follows a dry season in the mountains, the land can change abruptly. for example, a can rush downhill as a huge mass of soil, water, and rock, leaving a bare scar in the hillside.
a.
mudslide
b.
volcano
c.
earthquake
d.
glacier

A. mudslide.

Explanation:

This abrupt change can alter the surface, like mudslides, they are formed of water, rocks and water, like is described. This mudflow is capable to destroy vegetation, and leave behind fissures.

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.