How have U. S. peace negotiations with the Middle East affected the lives of Palestinian refugees? a positive effect; refugees have been granted peaceful existence in the countries of Iran and Iraq
a negative effect; refugees have been thrown out of several countries as a result of the terms of various peace treaties
no effect; refugees still remain without a place to call home
no effect; but the U. S. has worked to transport all Palestinian refugees to camps in the States

no effect; refugees still remain without a place to call home

Explanation:

The U.S. peace negotiations with the Middle East on the lives of Palestinian refugees have shown that there is "no effect; refugees still remain without a place to call home"

This is evident in the fact that according to the United Nations Relief and Works Agency for Palestine Refugees in the Near East, more than 5 million Palestinian refugees are still without a place to call home as they continue to live as regugees.

d) a constitutional amendment

the us constitution is a living document, meaning that it can be changed over time as the country changes.