Final answer:
Resistant starches, whole grains, and bacteria are substances that escape digestion and absorption in the small intestine.
Step-by-step explanation:
The substances that escape digestion and absorption in the small intestine are resistant starches, whole grains, and bacteria. Resistant starches are a type of starch that resists digestion in the small intestine and reaches the large intestine where it is fermented by bacteria. Whole grains contain fiber that is not digested or absorbed in the small intestine but helps propel food through the digestive system. Bacteria in the large intestine also play a role in breaking down indigestible substances.