The answer i believe is d.
hope this helps!!
The barrier is cultural differences.
John, growing up in America learned that eye contact is a way of respect and to show you are paying attention.
Where Cho, growing up in Asia, many Asian counties don't have this "custom" to call it that.
The supporting structure of the cell that is also involved in movement is most likely the cytoskeleton.
a. chloroplast and cell wall
The chloroplast contains chlorophyll, which is the stuff that makes plants green. So animals do not have a chloroplast. Only plants have a cell wall and it is what helps plants maintain their shape. Hope this helped! :)