Which of the following statements about diffusion is true?
"1. It requires integral proteins in the cell membrane. 2. It is very rapid over long distances. 3. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. 4. It is an active process in which molecules move from a region of lower concentration to one of higher concentration. 5. It requires an expenditure of energy by the cell."

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants