Homework question on Philosphy

I needed help with these questions

1.  What are  some of the implications to the claim that morality is whatever a culture deems normal? Is this view plausible? Explain why or why not? 

4)  According to ( the author), how do the concepts of moral progress and moral equivalence count against ethical relativism? 

5)  According to the text, how are contradiction and disagreement a problem  for ethical relativism? Are these problems fatal to the theory?Explain in detail why or why not it may be the case