Anyone can be involved in gymnastics, the people who compete in gymnastics are called gymnasts.
People who do gymnastics are usually called gymnists.
For team gymnastics two people are tumbling at a time.
Yes, they do.
Girls do compete in gymnastics in the olympics. They compete in four exercises: Balance Beam, Floor, Uneven Bars, and Vault.
in gymnastics you don't "score goals" you compete and receive points.
Balance in Gymnastics is when you use the balance beam to compete or use for recreation.
that means that you do not compete on it. Instead you just compete on the other events.