Imagine you have a big room where you store all your toys. Now, you want to put them in order and organize them in different groups. For example, you can put all the dolls together, all the cars together or all the building blocks together. This way, you will know where everything is and you can easily find the toys you want to play with.
A functionally classified barn is like your toy room, but it's for animals, not toys. Let's say you have a farm with cows, horses, pigs, and chickens. You want to keep them safe and healthy, so you need to create a barn that is suitable for each type of animal. It's not necessary to keep every animal in the same place because each animal has different needs.
For example, cows need a lot of space to move around, so you need a big area for them to eat and rest. Horses need a lot of exercise, so you need to have a big stable with enough space for them to run around. Pigs need a place to lay down and roll in the mud, so you should have a space for them to do that. And chickens need a coop to rest in and lay their eggs.
In a functionally classified barn, you are grouping the different animals according to their specific needs. This makes it easier to take care of them and keep them healthy. It also helps to keep the barn clean and organized, so you can find everything you need easily.
So, you can imagine a functionally classified barn is like your toy room, but instead of grouping toys, you are grouping animals according to their needs so that they have a safe and comfortable place to live.