A Yeerk is a parasite and its DNA is separate from the DNA of the host. Well. . . similar. We were wondering if we're right. As for an all-out invasion, you need to remember that the Yeerks are a parasite species, not predators. They don't want to kill humans, they want to infest them.
Humans do have the ability to defend themselves, after all.
Maybe we wouldn't win, but it would be messy before we lost. Dear Ms. Applegate, I have read all your books. Once I read one book, I couldn't stop. You got me hooked on reading and now my mom is really happy that I am reading. I can't wait until I get all the series of Animorphs and Megamorphs.