Politics means the world of government in general:
The vice-president has a long career in politics.
I hate discussing politics with my family because it always turns into an argument.
Sometimes people talk about "office politics" outside the context of government -this means the connections and actions that people inside a company take in order to gain power, forming relationships and manipulating situations to their advantage.
A policy is like a rule. Countries have policies (foreign policy, immigration policy, gun control policy) but schools and companies do, too:
Our policy is that customers can return an item and get a refund within 30 days of their purchase.
My school had strict policies regarding lateness - if you were late more than five times, you got suspended.
Banana leaves contain large amounts of polyphenols such as epigallocatechin gallate, or EGCG, also found in green tea. Polyphenols are natural antioxidants found in many plant based foods. According to an article by Augustin Scalbert and colleagues published in the January 2005 issue of the American Journal of Clinical Nutrition, extensive research is ongoing to help determine the extent of how polyphenols affect human cells, the oxidative process and its impact on disease prevention.