What did alexander fleming discover that solve a societal problem?

Alexander Fleming discovered penicillin, the most important drug that destroys bacteria within the human body. This discovery has led to the prevention of many diseases and untimely deaths in society. He was a pharmacologist, botanist, and biologist that won a Nobel Prize in Physiology for his major contributions in developing antibiotic substances. 

1. “what forms of energy conversions occur during the process of photosynthesis? (How does energy transform?) 2. What is missing from the food web but is essential to maintain equilibrium? A. Soil B.water C. Decomposers D. Oxygen