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.
False in order for an ecosystem to survive there has to be some sort of competition. for example, if there were no sharks to eat little fish the little fish would over populate and then the little fish would run out of food which then means that whatever the little fish ate is now extinct and so on hinting the food chain's name. If it wasn't for competition nothing would survive
c. Adenomyomatosis. it's an abnormality of the gallblader mucosa