Complex sentence: The spray of skunks consists mainly of low-molecular-weight thiols and derivatives that can smell bad as the smell protects skunks from predators such as humans and wolves; however, owls can prey on skunks as they are unable to smell the thiols.
Split into simpler sentences: The spray of skunks consists mainly of low-molecular-weight thiols and derivatives. Owls can prey on skunks as they are unable to smell the thiols.