*Please help?*

Why was slavery a paradox in the United States?

A) People in the North refused to allow escaped slaves to live in their states.

B) The Supreme Court ruled that slavery was illegal.

C) Slavery had existed throughout the world for thousands of years

D) It went against the ideals of freedom on which the nation was founded.

What important discovery was made by edmond halley and alexis clairaut, using newton's ideas of mathematics and gravity? they created the scientific method to outline how science should be conducted. they were able to find the orbit of a comet and predict the year of its return. they discovered the three newest planets--uranus, neptune, and pluto. they explained why objects appear to have color.