Answer:
A technology, since the actual prosthesis is a human creation that solves a problem. Science is nothing physical. It is the combination of laws and theories that explain our universe and helps us make decisions. We don't really invent science, we describe it.
Science is ideas. Technology is human creations.
Science generally underpins all new technology.
In your human leg prosthesis example science is crucial in choosing (or developing) suitable materials for construction of the prosthesis. The material must be relatively stable, not break down into toxic substances and have good durability. Knowledge of human Biology is also important if you want to start replacing human body parts.
Basically chemistry and biology are important in the prosthesis development. There is also probably physics regarding tensile strength requirements.
The actual end result of the human prosthesis is a technology which solves a problem of degraded human parts.
So to reiterate, it is a technology.
Step-by-step explanation: