All our physical substance comes from water, air and eating. We are part of the food chain . Like all animals, we must eat other living beings or die. Aside from water or air almost every molecule, speck or atom in our bodies comes from or through another living being. I don't have to tell you how living beings make food.
Farmers always joke about city kids who think that milk comes from bottles.
Perhaps farmers know more about the connection between things than we do in the city and we can learn a particular view from the farmers. Food originates with photosynthesis . For most of human history people got their food by gathering and hunting. Their impact on the environment was not as small as some like to imagine. They burnt forest, hunted certain species to extinction, and modified the environment in their favour to whatever extent their technology and understanding would allow.