Describe how changing the rate of vibration can vary the pitch of a sound

Why was frederick douglass encouraged by the dred scott decision?

On a supply and demand graph, equilibrium is the point where the two curves meet. the supply curve begins. the supply curve ends. the demand curve ends.

“obamacare”: included a provision for government-run health insurance called “the public option.” was bitterly opposed by congressional republicans because most favored a “single-payer” plan. survived two challenges to its constitutionality. was partially repealed in 2013 in order to avert a government shutdown. led to the expansion of medicaid in republican controlled states.