Three moles of gas expand isothermally at 0 degree from initial pressure 5 atmosphere to final pressure 3 atmospheres. how much heat is absorbed

Although longitudinal waves can travel through all media types what is the disadvantage of this type of wave transmission? a) he efficiency of he wave transmission is greatly diminished as the media becomes less dense b) the oscillation of one set of particles has a huge impact on neighboring particles c) particles become too close together as they bump into each other making it more likely to hit other particles down the line

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration