The answer B.Since,Diffusion is driven by differences in concentration. When chemical substances such as perfume are let loose in a room, their particles mix with the particles of air. ... Diffusion in gases is quick because the particles in a gas move quickly. It happens even faster in hot gases because the particles of gas move faster.
D.
Anytime the word most is used with an adv. it makes it superlative
The answer is A. Because a chart showing brain size of various animals tells the intelligence of each animal and also compares them.
