Based on the video, what is the function of tRNA molecules? tRNA molecules copy the information contained in DNA. tRNA molecules bring amino acids for the ribosome to link together. tRNA molecules move proteins out of the cell. tRNA molecules move along a section of DNA and unzip it.

Sorry i don’t know what to do

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. 

'b ' is the correct conclusion.

D. the index of refraction of the second medium is lower.