Julie sets up a uniform lever with the mid-point of the lever sitting on the pivot She places one weight on end Y of the lever as shown

Carefully, she puts an equal weight at end X
What will happen to the lever?

The lever will not move.
The lever will move to the horizontal position.
The lever will move past the horizontal position and
then return to the horizontal position.
The lever will come to rest with the end Y on the horizontal
surface.

Gravity bc it’s gravity

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. 

Shania is trying to determine the oldest geologic unit on this map and the reason to why is she unable to do so is that  the units are all the same age.. when there is the same age, there will be no oldest geologic unit and that i cannot be credible.