Which of the following statements is true of combustion reactions? a. hydrogen gas (h2) must be one of the reactants b. water (h2o) is always a product c. energy is released by the reaction d. carbon monoxide (co2) is always produced

Crust,mantle,core,earth

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