Rheumatoid arthritis is a disorder in which the joints swell and cause pain. Rheumatoid arthritis causes the body’s own immune cells to attack the membrane of the joints. Which body system does rheumatoid arthritis affect? A.
nervous
B.
musculoskeletal
C.
integumentary
D.
excretory
E.
circulatory

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.

When you go to ask a qustion there will be a picture of a paper clip looking thing and then it will pop up your files and you click on the imajes and then you up load it

The answer to the question is (a)