Avoltaic cell differs from an electrolytic cell in that in a voltaic cell
a. energy is produced when the reaction occurs
b. energy is required for the reaction to occur
c. both oxidation and reduction occur
d. neither oxidation nor reduction occurs

The answer is A. Voltaic cells couple oxidation and reduction half reactions to produce electromotive force from chemical potential energy. Electrolytic cells do the opposite in that they require electromotive force to store chemical energy.

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