How many cells thick is the
lining of the small
intestines?

One cell layer

Explanation:

You can see that this type of epithelium, which is lining the lumen of the jejunum of the small intestine, is a simple epithelium. It is only one cell layer thick and columnar, as the cells are rather tall.

exposure to hazardous carcinogens and toxic substances can cause breathing problems, such as copd and various types of cancer. it also increases the risk of heart attacks and strokes and has serious (but no less unattractive) side effects, such as aging, yellow teeth, a terrible smell and damage to the vocal cords.