Hardy-Weinberg equilibrium requires no immigration or emigration, a large population, random mating, and no spontaneous mutations (all of which are virtually unavoidable in nature). Natural selection would violate these conditions.
Explanation:
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.
Your right it is mutation
The sclerenchyma is the tissue in which creates the plant firm and hard. The two kinds of sclerenchyma cells exist fibers and sclereids. Their cell walls be made up of cellulose, hemicellulose and lignin. The sclerenchyma cells are the principal associate cells in plant tissues that have come to a close elongation.
The answer u r looking for is- A, Vestibulocochlear. Hope I’ve helped ;)
