Answer:
D
Explanation:
I just had this question the answer is D
Compression and rarefaction are two phenomenon occurs in longitudunal wave!
when there is denser particle gathering in that wave , there we called it compression and the rarer part of particles is rarefaction !
Atoms are basically tiny structures that make up everything. And a compound is something used in a scientific expirement. I don't get the question. You used improper grammar