Why do chemists use relative masses of atoms compared to a reference isotope rather than the actual masses of the atoms?

When were the first 10 amendments to the constitution adopted and what was their purpose? when were the first 10 amendments to the constitution adopted and what was their purpose?

What restrictions do you think should be placed on studies with animal participants? explain

“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 was partially repealed in 2013 in order to avert a government shutdown.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.