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.
The sentence which is the most objective is <span>A. My mother taught Italian lessons at the community center.
</span>It is a fact, therefore it is objective. The other sentences are somebody's opinions - stupid sisters, crazy Greek family, a real pain - these words show that it is someone's opinion, which is subjective, not objective.
