Applying bass and treble

I am selecting a portion of my audio, when I select bass effect it applies this to whole audio? what is wrong

Please describe step by step exactly what you are doing, what you expect to happen, and what actually happens. Ensure that your description is sufficiently detailed and precise that someone that can’t see your computer will be able to exactly reproduce the same problem.

I highlighted a portion then clicked on effects bass and treble then increase bass,
when i select any other portion after applying bass I find all the audio has the same bass

I’m guessing that you mean the “Effects” button on the left end of the track. That adds “real-time” effects to the track, and they apply to the entire track.

To apply an effect to a section of the track, use the effects from the"Effect menu" near the top of the main Audacity window.