One similarity between work and power is that in order to calculate both you must know time, velocity, energy, or force

To calculate the work and power we must know about the time, velocity, energy or force

Power is work over time

P = Wt

Where P is power, W is work and t is time

And W = Fd x cos(theta)

Here F is force and d is the distance

And d = velocity x time

If we replace d with velocity and time, it shows that to calculate Work we must know time, velocity, energy or force

And if we replace the formula to calculate work in P=Wt, it also shows that to calculate power we must know the time, velocity, energy or force.

a. is the answer because they are not shared

3. dark matter

empty space could also be a simple vacuum