Question

Question was provided via image upload.

Explanation:

Collision theory states that for a reaction to occur, particles must collide. Successful collisions require proper orientation and sufficient energy. The first option matches this: particles need to collide to react. The second is wrong (orientation matters), third is wrong (temperature increase increases kinetic energy), fourth is wrong (reactions start with particle collisions).

Answer:

A. Particles need to collide in order to react.