What is a buffer used for? A. To limit the pH change in a solution
B. To prevent an acid from dissociating
C. To neutralize the pH of a solution
D. To prevent a salt from dissolving

I would say that it is C

A, a buffer is used to limit or to stop any change to the pH in a solution.

Ithink it’s a forms a perfect sphere or a smooth flattened oval

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later