Hello!!!!!
my name is Ana and I`m trying to do mi science proyect.
My big question is if can plants grow from leaves

Ana, there ae two answers to your question. One is that any plant can grow from a piece of a leaf in a laboratory with some very complicated treatments (possibly years of looking to work out just what to do). The second is that for a gardener, most plants will not grow from leaves. Some are known to do it very well - African violets and their relatives and many begonias and lots of the plants in the kalanchoe group.
So, I don't know what experiment you are trying to do, but you have taken on a very difficult project, and probably one that will noy give you results in te time available. if you have to stay with this idea, get some Kalanchoe and see how the size of the piece of leaf that you work with affects the success rate. That might give you results fairly quickly. Derek