They are indicators of Arsenic poisoning
I think it may be B,A,OR D
MgCl2 dissolves in water because the individual ions in the solid (Mg2+ and Cl-) coordinate with the partial charges in the water molecules. The magnesium cations coordinate with the partially negatively charged oxygen atoms and the chlorine anions coordinate with the partially positively charged hydrogen atoms.
Fossae are holes or depressions in the bones that are usually found on the end of the long bones. Fossae are good indications that a bone was connected or articulated with another bone. Therefore, if a scientist has found a fossa on a bone he or she could conclude that the bone was joined with another bone in the skeleton at the place of the found fossa.
