TASK DEFINITION: Given a scientific question, generate a correct answer to it.
PROBLEM: Radioisotopes may vary greatly in their rate of decay, decaying faster if their nuclei are more what?

SOLUTION: unstable

PROBLEM: Each cell and every living thing requires what?

SOLUTION: energy

PROBLEM: The extracellular fluid is in contact with the axon membrane only at what location?

SOLUTION:
the nodes