Which thinker is credited with establishing the basic principles of physics, including natural laws that govern gravity and motion?

Which of the following world and national events led to a new view of people with disabilities in the us:     a.  world war i and ii veterans with disabilities returned home after the wars.b.  john f. kennedy was elected president and had a sister with a disability.c.  the civil rights and feminist movements.d.  all of the above.