Final answer:
The concept of 'sky land' seems fictional, and in such a case, food could come from fantasy elements such as magic. In real-world biology, food is produced through photosynthesis in plants and the food chain, which would also apply to any hypothetical ecosystems in the sky.
Step-by-step explanation:
The question, 'Where did all of the food in sky land come from?' seems to be a hypothetical or fantasy-based scenario rather than a real-world phenomenon, as there is no known place as 'sky land'. In fantastical or fictional settings, food could come from a variety of sources such as magical plants, animals that live in the sky, or other supernatural means.
In a literal sense, however, the biology of how food is produced involves processes like photosynthesis in plants and the food chain that supports animal life. If one were to envisage an ecosystem in the sky, it would still require a source of energy (like the sun) and a series of organisms that can generate food from that energy and subsequently serve as food for other organisms.
In real-world biology, food comes from the ground as plants convert sunlight into edible matter, and animals either consume these plants or consume other animals. This biological process is driven by the planet's ecosystems and the various roles organisms play within them.