Answer:
1. Alleviate: to make pain/suffering less severe.
2. Strenuous: requiring much energy and effort.
3. Revolutionize: to overthrow the established government; to change fundamentally.
4. Repetitive: doing or saying the same thing multiple times.
5. Prosthetics: a device designed to replace a missing body part, or make a part work better.
6. Infrastructure: the fundamental facilities and systems serving a country, city, or another area, including the services and facilities necessary for its economy to function.