Research diffusion and how it relates to the human body. E. G. red blood cells and oxygen

nside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.

answer; ///i believe the correct answer is (aids) acquired immune deficiency syndrome;

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.