how the American core value of individualism can stand in the way of seeing the interdependence of people?

I don't think you've got it yet...and I don't think I understood your example.

I see it this way - there are many people who object to paying taxes because they feel "it's my money...I earned it. What right does the government have to take any of it?" They think of themselves as individuals, not as a part of a larger society, so they feel no responsibility to contribute beyond their own narrow interests. They vote no on school budgets because their children are no longer in school - they don't think that public education benefits them personally, so they don't want to contribute...they don't see that a better educated population benefits all of us.

Hope that example helped.

I'll play devil's advocate to the first answer.  Interesting homework assignment by the way.  I agree that you aren't grasping what each word means, interdependency and individualism.  Grab yourself a notebook and start jotting things down, starting with the definition to each one.  
Here's an example of what it means:
You have an assignment at school and you are assigned into groups.  Now, let's say that one member of the group does all the work.  Should the group receive the same grade or does the individual who has done all the work receive the better grade, while the rest of the group fails?  Okay.  Same situation.  Let's say that three people are in the group.  And one person has limited access to resources in order to complete the project.  We'll use a computer.  So, a majority of the project is computer-work.  Should the person who has the computer receive a better grade because that person did more work due to resources, while the rest of the group receives a lesser grade?   How does each situation's outcome benefit the individual who did the majority of the work/or all of the work and how does any outcome benefit the group?  Also, how does outcome hurt the individual or hurt the group?   Now, this situation.  A group project is assigned, everyone has equal access to resources to complete the group, but not everyone contributes equally?  What limitations does each person have?  Does one person's limitations stop them from receiving the same grade as someone who doesn't have the limitations?(like a learned disorder)  
Now in all situations, who decides what is best for the group?   That is the constant argument with individualism and interdependency.   Individualsim is the "right" to advance yourself as far as you can
Interdependecy is the right to equal portions all around, no matter who contributes or how much any one member contributes.