You are given three test tubes. The three test tubes contain distilled water, acidic solution and the basic solution respectively. There is only blue litmus paper available in order to identify what is there in each test tube. How will you find out what is in each of the test tubes?

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

The answer is d. hope i !