The major function of the immune system is to protect the host from environmental agents such as microbes or chemicals, thereby preserving the integrity of the body. This is done by the recognition of self and response to non-self.
<span>For the answer to the question above, I'll just complete the sentence for the answer to your question. "Radial" are characteristics of downcutting streams and a youthful stage of valley evolution.
I hope my answer helped you in someways
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