In practice, something that follows a very predictable pattern can be used as a time standard. This include things like radioactive decay, planetary orbit, and the speed of light, among others.
Answer:
B . energy cannot be created or destroyed
I = E / R
If the resistors are in series, the current is 0.3 Amperes.
If the resistors are in parallel, the current is 1.25 Amperes.