Collision Theory: For a reaction to occur, reactant particles must collide with sufficient kinetic energy ($E_{\text{coll}} \ge E_a$) and favorable geometric orientation.
Maxwell-Boltzmann Speed Distribution: Higher temperature shifts the molecular speed distribution to higher energies, exponentially increasing the fraction of particles with $E \ge E_a$ ($f = e^{-E_a / RT}$).
Catalyst Action: Catalysts provide an alternative reaction pathway with a lower activation energy barrier without being consumed.