To help food digest and help it to be absorbed more efficiently.

No . A molecule of triglyceride is composed of a molecule of glycerol in ... Triglyceridescannot be efficiently absorbed, and are enzymatically digested by pancreatic lipase into a 2-monoglyceride and 2 Free fatty acids. All of which can be absorbed. Other lipase's hydrolyse a triglyceride into glycerol and 3 fatty acids.

Finger like folds in the intestines called villi and microvilli aid in the nutrients being absorbed into the bloodstream. The function of the villi in the frog is it helps with the digestion process.

Oatmeal contains fiber, so no; fiber slows down the digestion process, allowing moisture to be absorbed more efficiently. If anything, your fecal matter should be incredibly dry, and painful.

There is no known good natural source of vitamin D other than exposure to sunlight. If needed, there are always Vitamin D supplements, however these aren't as efficiently absorbed compared to the natural source.