Head / neck
Your bones and skull, they protect all your vital organs from damage, if you are hit for some reason.
how does residental normal flora protect the body against pathogens
Of course, if it's part of your body, it's a body part.
The immune system helps protect the body by removing bacteria and foreign bodies.
To protect the wearer's neck
I connect it to the French word for throat which is gorge,thus derives the word gorget ,a small armored plate to protect the throat in battle (sabre cuts),
Skull bones protect your brain.
The gorget fitted around the neck of a knight whilst protecting it
skin
the spinal cord
Eyelids and Eyelashes.
Its exoskeleton.
by wings
scales
Your hands! :P
the head