It sounds paradoxical, because the idea behind this hypothesis is that the red pigment is made in autumn leaves to protect chlorophyll, the light-absorbingchemical, from too much light.
Breaking down food, absorbing nutrients, and expelling of waste requires chemical processing, mechanical mixing and rhythmic muscle contractions that move everything on down the line.
分解食物、吸收营养，排出废物，则需化学反应，机械搅拌，肌肉韵动三方协作。
3
Chemical neutralization reactions play the main roles in the process of absorbing SO2, and physical adsorption is secondary.