What can we use to determine the relative age of two rocks

You can use the law of superposition:in horizontal sedimentary rock,the oldest layer is at the bottom.the more layers up is younger than the ones under

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

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