When did our current constitution become effective

Dalton developed the first model of the atom that showed the structure of the inside of an atom

Which action by the us war department angered chief red cloud to the point that he refused to sign the treaty of fort laramie ? a) the killing of buffalo by the united states troops b) the appointment of troops to the powder river basin c) the burning of parts of the powder river basin d) the murder of chief red cloud’s wife

According to some historians which marks at the beginning of the us civil war