To cause the reaction to become darker brown means to produce more of NO2 gas. That is backward reaction.
Since the reaction is endothermic, decrease in temperature will shift the equilibrium position to the left thereby favouring backward reaction. This is in line with Me Chatelier's principle.
High pressure will rather favour forward reaction (it is not the right option).
A) The temperature at which the particles of matter are at their lowest energy points.
Explanation:
Absolute temperature refers to the lowest possible temperature. At this state, no heat energy remains in the substance; the energy of the particles are at their lowest energy points.
