Answer:
cellular respiration...that's breathing out of humans
and through human activities like burning of fossil fuels...
Answer:
They enable protein production.
Explanation:
In contrast to the stratified squamous epithelium of the skin, the intestinal barrier is composed of a single layer of columnar epithelial cells However, this single layer of intestinal epithelial cells is made of diverse cell types with absorptive, secretory, and immune function
