If you were asked to convert 25 kg to the unit mg, which of the following would be the first fraction used in the conversion?

To convert the unit kg to mg, the result needs to be written in scientific notation. And 1 kg = 10^6 mg. So the answer is 2.5*10^7 mg.

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