1. You decide to test whether charcoal helps purify water or not. You design a filter that contains charcoal and run water from a nearby stream through the filter. Afterward, you test the water for contaminants. Independent variable:
Dependent variable:

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