The answer is A. Carbon dioxide dissolving into clouds and forming acid rain
<span> B. White blood cells move through the body (to
parts where they are needed) in the blood vessels of the circulatory
system to destroy pathogens.</span>
Smooth, rounded characteristics such as large eyes, fat cheeks, and a large head (i.e. babies) is very appealing to humans and other species (the way we call it "cuteness") which is a stimuli that promotes caring of babies and young children. This is also the same principle why humans find puppies, kittens, and other baby animals cute and want to care for them.
By diffusion. Letter c.
Diffusion occurs when the smell of the bread "sticks" to the air and if the air travels from a room to another, the smell will go with it.
Hope it helped!