a predator is a kind of animal & most animals avoid bad odors ->  most predators avoid bad odors  most predators avoid bad odors & a skunk produces a bad odor ->  most predators avoid skunks because they produce a bad odor  most predators avoid skunks because they produce a bad odor & causing predators to avoid you is a kind of method for avoiding predators ->  producing a bad odor is a kind of method for avoiding predators used by skunks  producing a bad odor is a kind of method for avoiding predators used by skunks -> producing a bad odor helps skunks avoid predators