I think, if it wasn't for biology, we would have not much idea of how to treat our bodies well. Like, drinking water, eating certain foods (for the brain, liver, heart etc.) and exericising. I think, that if someone didn't actually sit down and do the work, we may all just be living by trial and error, and many people would be confused and frustrated why they aren't healthy and bouncing off the walls. I'm very grateful to science, otherwise, a lot of us may be dead. Particularly without medicines, which are made to treat specific tings (by blocking certain hormones, of increasing certain enzymes in the body, or helping repair receptors that wouldn't otherwise be able to heal). Simple surgeries such as removing the appendix, and skin caners, would not be done, as we would likely have no idea why they affect us, or how to actually get there and treat it properly.
Well since Biology means the study of living organisms, divided into many specialized, and plants and animals of a particular area, then with out biology we would not exist... consider your life better! :D
Oh and also.. with out the knowledge of biology.. we wouldn't have many of the medication that we have today.