What are the benefits of turning in research and where can I see them?
Take a look in your codex entries for creatures. As you flip through the cards, you'll see black and white pips in the upper right. One pip means you have descriptive text. Two pips means you have an advantage. Scroll to the bottom of the descriptive text to see the advantage you unlocked.
If you've turned in some material for a given creature codex entry, you will also notice a progress bar displayed on the card.