Apolar covenant bond is likely to form between two atoms that
a.) are similar in electronegativity
b.) are of similar size
c.) differ in electronegativity
d.) have the same number of electrons

A polar covalent bond is likely to form between 2 atoms that are C. Differ in electronegativity.

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