The difference between a restrictive phrase and a restrictive clause can be determined if you break down the parts of speech. It is a clause if there is a subject and verb with a predicate. It is a phrase if there is a noun but no verb or a verb but no noun, and it does not have a predicate.
Intruder because that is something unwanted
The first one is right. it joins two independent clauses with a comma followed by a conjunction.
I think it's a reflex action because it would be what your mind and body is conditioned or believes should be done.
