How and why do amendments become part of the Constitution?

Resources: The United States Constitution and the 27 amendments in Appendix A of Constitutional Law and appropriate websites
write a paper on Thirteenth through Fifteenth Amendments
How and why do amendments become part of the Constitution?
What problems with the original document motivated the adoption of the Bill of Rights?
What have been the effects of the Bill of Rights?
What problems with the original document, or changes in society, led to later amendments?
What have been the effects of these later amendments?
Include introduction and conclusion
Cite at least three sources to support