What holds combinations of atoms together in molecules? protons and electrons atomic magnetism chemical bonds nuclear forces?

Chemical bonds hold combinations of atoms together in molecules. These chemical bonds, called covalent bonds or molecular bonds, are formed when two atoms share electron pairs. Some other types of chemical bonds are ionic bonds and metallic bonds.

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