Why are there 3 types of gymnastics?

Actually there are 6 types under the heading gymnastics. These are: Artistic, Rhythmic, Acrobatic, Aerobic, Tumbling and Trampolining.

Each different types arose due to different areas being incorporated within the FIG. Artistic uses the apparatus, Rhythmic uses the 5 portable apparatus, Acrobatic uses the floor as a pair or team without apparatus, Aerobic is like doing vigourous exercise on the floor, Tumbling uses a 25 metre springy mat and Trampolining obviously uses a trampoline.