A student wanted to use toilet paper to show the distance of one Astronomical Unit, or the distance from the Sun to Earth. They decided to use a scale factor of 1 square of toilet paper = 100,000 km.
How many rolls of toilet paper will the student need, if each roll of toilet paper has 500 squares?

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 c) pyrite