Of the following, which are TRUE about collision theory? (select all that apply) Select all that apply: aa. Collision theory explains why reaction rates tend to increase with higher concentrations. b. Collision theory states that reactions can occur without properly oriented collisions c. Collision theory states that, in addition to a collision in the proper orientation, adequate activation energy is required for a reaction to occur. d. Collision theory explains that more frequent collisions lead to a faster reaction rate.