What means invertebrates have only nonspecific immunity which?

Invertebrates possess only nonspecific immunity, meaning they rely on general defense mechanisms rather than specialized responses to specific pathogens. Their immune responses include physical barriers, such as exoskeletons, and cellular responses like phagocytosis, but they lack adaptive immune systems that characterize vertebrates. This nonspecific immunity allows them to respond rapidly to a wide range of threats, but it does not provide long-lasting protection against specific pathogens.