Biology gives us many alternatives to the immune system, which is found only in vertebrates. https://en.wikipedia.org/wiki/Innate_immune_system#Beyond_vertebra

Biology gives us many alternatives to the immune system, which is found only in vertebrates. https://en.wikipedia.org/wiki/Innate_immune_system#Beyond_vertebrates https://en.wikipedia.org/wiki/Innate_immune_system#Beyond_ve...