Answer with Explanation:
Stephen Hawking was an English cosmologist and physicist who became popular for his theoretical predictions, such as the "Hawking radiation."
However, he became gradually paralyzed owing to a motor neuron disease. He became an advocate for people starting in 1990 wherein he participated in fundraising events for the disabled. Together with other influencers, he signed the "Charter for the Third Millennium on Disability." This protected the rights of the disabled, with the help of the government.
On the other hand, Ed Roberts was an American activist. At a young age of 14, he contracted a polio disease. This didn't stop him from going to school. He used a wheelchair in attending his classes at the University of California, Berkeley. He became an advocate for the disabled after he experienced discrimination of not being given a diploma by his school due to having no driver's license and not completing the physical education class. He also provided services which assisted the disabled people.