Not a clue but you should study
they help us see because the retina also contains the nerves that tell the brian what the photoreceptors are seeing
Bones are made up of Calcium Phosphate given by the chemical formula, 
. When bones are kept in Hydrochloric acid, given by the chemical formula, HCl, they become soft because the calcium compound present in the bones changes its form. The following double displacement reaction takes place when the bones are kept in HCl,
---> 
Calcium chloride is water soluble, and gets washed away. This makes the bone thin and soft.
I think they are called Sutural. Intra sutural bones also known as the wormian bones are extra bone pieces that occur within a suture (a joint) in the cranium. They are irregular isolated bones that appears in addition to the usual centers of ossification of the cranium and they are not rare bone despite being unusual.
