Your weight pushing down on the chair is the action force. The reaction force is the force exerted by the chair that pushes up on your body.
Hmm, I will come back to this one just to help. :)
13-16 that is where they’re located at
"Frequency decreases" is the one way among the following choices given in the question that <span>frequency change as wavelength increases. The correct option among all the options that are given in the question is the second option. I hope that this is the answer that has actually come to your desired help.</span>