Answer:
I think its the
d. The body's own defenses
I would say that the first answer choice makes sense since the charge of Oxygen is +2. But I may be wrong, try it out!
Answer:
This is because of diffusion , the movement of particles from an area of high concentration to an area of low concentration. ... This means that diffusion does not happen in solids – the particles in a solid can only vibrate and cannot move from place to place.