My textbook has a chapter on Waves, focusing specifically on Mechanical ones. It says the following statement for the Transverse and Longitudinal waves.
Transverse waves only travel in a medium which opposes tensile force while longitudinal waves travel in mediums which can exert an opposing compressive force.
The book doesn't state any examples for the above statement, which confuses me. I know the basics of how waves travel, but why is opposing tensile force and compressive force necessary? I think there is some gap between what the book wants to convey and what I am understanding at my level. Any help will be greatly appreciated. If you could suggest some text for background reading, it would be even more helpful. Thanks a lot in advance!