The answer is B, or They can survive in changing salinity.
Ur answer is number 2 i'm almost sure of i
The 2 types of bone markings being identified would be the opening on the occipitomastoid suture in which the internal jugular veins would travel to carry the blood from one's brain to the heart and the Mandibular condyle of the mandible that would then form the temporomandibular joint.