What discovery did Newton argue was a main force in the universe?

Gravity

Explanation:

1. international: struggle for hegemony and empire outstrips the fiscal resources of the state

2. political conflict: conflict between the monarchy and the nobility over the “reform” of the tax system led to paralysis and bankruptcy.

3. the enlightenment: impulse for reform intensifies political conflicts; reinforces traditional aristocratic constitutionalism, one variant of which was laid out in montequieu’s spirit of the laws; introduces new notions of good government, the most radical being popular sovereignty, as in rousseau’s social contract [1762]; the attack on the regime and privileged class by the literary underground of “grub street; ” the broadening influence of public opinion.

4. social antagonisms between two rising groups: the aristocracy and the bourgeoisie

5. ineffective ruler: louis xvi

6. economic hardship, especially the agrarian crisis of 1788-89 generates popular discontent and disorders caused by food shortages.

d is the best answer for this question.