Which explains why an activated complex is a high-energy species? activated complexes form during endothermic reactions. activated complexes require new bonds to be made. activated complexes are stable species with strong covalent bonds. activated complexes cannot be formed in the reverse reaction direction?

I think the correct answer is the second option. An activated complex is a high-energy species because activated complexes require new bonds to be made. Activated complexes are unstable arrangement of the atoms that happens rapidly at the peak of the energy barrier. So, they would normally have high kinetic energies.