Part 2 of 3. Tonight’s concluding installment, “We Are What We Eat,” breaks down foods into key components, then breaks down some of the cooking methods to explain exactly how the preparation of certain foods alters what happens to them in the process, and how those results affect us afterward. Watch, in particular, for a segment on baking, where it’s explained how the chemical reaction sparked by kneading breads leads to the production of gluten, and the chemical reaction that leads to the rising of dough. When baking bread, because it’s so tricky a science and so fussy an art, you can’t always get what you want – but if you try sometimes, well, you just might find you get what you knead. Check local listings.