Question:
If all matter were made of electrically neutral particles such as neutrons (a) there would be no force of friction
(b) there would be no tension in the string
(c) it would not be possible to sit on a chair
(d) the earth could not move around the sun
Solution:
If all matter were made of electrically neutral particles, then there would be no friction, no tension in the string and also it would not be possible to sit on a chair. But earth could move around the sun as it is due to gravitational force.
(a), (b), (c)