As a student, I way too often see uneaten fruits or vegetables simply being thrown away after someone "finishes" their lunch at school. This is bad for multiple reasons: One, fruits and vegetables are a necessity for a healthy and nutritious meal. While you don't necessarily need to have some every meal, it's important that by the end of the day, your vitamin and mineral needs have been satisfied by the consumption of fruits and vegetables. Therefore, when a student skips their produce, they are skipping on these vital nutrients that they depend on to being a fully functioning and healthy being. That's not to mention the valuable energy that fruits and vegetables bring to the table. Two, there are so many malnourished people in the world that would've gone to extreme measures just for a fresh apple that some student may have thrown away. It's an indirect spit in the face for them every single time a piece of fresh produce is wasted. Third, and the reason why you're here right now, climate change and the environment. There's a ton of energy and water that get put into growing, harvesting, transporting, and packaging the produce; all of which contribute to climate change. We not only waste a valuable source of food and energy when we throw away produce, but also all of the precious energy and water put into the whole produce process. Plus, a lot of the produce that gets thrown away eventually winds up in the landfill, which then contributes to the production of methane, a harmful greenhouse gas.
I hope that with all of this being said, you at least think twice before throwing away the apple you didn't finish at lunch, or perhaps didn't even touch. Or pack of carrots. Or corn. Or whatever it may be.