Medeleleev arranged the known chemical elements in a table according to

a) atomic number
b) number of electrons
c) number of protons
d) mass

A- atomic number.  Atomic number represents how many protons are in the element, and they are arranged this way in the table in ascending order.  

edit- on second thought they weren't technically known as atomic numbers until after he arranged them, so I guess the better answer in this case is d- mass.  It's a trick question since today they're considered arranged by atomic number

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