VOA:

It was only during the administration of president George Bush senior in 1989 that the ceremony became an annual event. After all this turkey represents America's 45 million Turkeys,

who will begin making their irreplaceable contribution to our Thanksgiving celebration, so take it easy turkey.

1) represents America's 45 million Turkeys， 可以把America's 替换成 American 吗？ 总是搞不清America's 和 American的区别？（就如搞不清China's 和 Chinese的区别一样）

2)  先行词 45 million Turkeys， 后面的定语从句用了关系代词who, 请教老师，动物也可以用who吗？（我一直认为只有人才可以用who）。