The louisiana purchase
a) nearly tripled the size of the united states.
b) improved relations between the united states and britain.
c) set the border between the united states and canada at the forty-ninth parallel.
d) nearly doubled the size of the united states.

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.