Which was the first to decrease? number of american troops in vietnam north vietnamese willingness to accept casualties number of bombing missions against the north domestic support for the war in the us

From this list of options, the first to decrease was "number of bombing missions against the North". This was followed by domestic support for the war and then troop levels. 

The first decrease was the 'number of bombing missions against the North.'

Cherokee  removal, part of the trail of tears, refers to the  forced  relocation between 1836 and 1839 of thecherokee  nation from  their lands ingeorgia, south carolina, north carolina, tennessee, texas, and alabama to the indian territory (present day oklahoma)  in  the thenwestern united states, and the resultant deaths