Which of the following is an example of how a scientist might use a model?
a.)a stopwatch is used to time the rate of a chemical reaction
b.)a microscope is used to magnify a group of cells on a slide
c.)the end of a slinky is moved vertically up and down to stimulate a wave
d)a wrench is used to tighten a nut onto a piece of wood

answer: secession

secession, as it applies to the outbreak of the american civil war, comprises the series of events that began on december 20, 1860, and extended through june 8 of the next year when eleven states in the lower and upper south severed their ties with the union. the first seven seceding states of the lower south set up a provisional government at montgomery, alabama. after hostilities began at fort sumter in charleston harbor on april 12, 1861, the border states of virginia, arkansas, tennessee, and north carolina joined the new government, which then moved its capital to richmond, virginia. the union was thus divided approximately on geographic lines. twenty-one northern and border states retained the style and title of the united states, while the eleven slave states adopted the nomenclature of the confederate states of america.

explanation:

roosevelt essentially took the opposite approach as hoover in taking on the great depression. herbert hoover thought that america and its economy could naturally recover from the depression in due course, so he adamantly restrained the federal government from intervening on behalf of the people affected. on the other hand, roosevelt dramatically increased employment by expanding the federal government and establishing agencies that would aid in relieving some of the country's worst problems.

answer; a farmer who refuses to fight in his country's army;

it required the unanimous approval of the states before the congress could enact any measure.