Since it is a organism, we know its a living thing.
Ex: Rock=not living=not organism
Plant=Living=Organism
If you studied it under a microsope, you would expect to see cells as every living thing has. A microscope is a tool used by scientist and are made to see very little things that our regular eyes and a magnifying glass cannot see. So you would see cells because cells are very very tiny
Can I see the models?? I don´t know what the cactus looks like/