What are two main purposes for using repetition when conducting experiments?

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction.

Why does the earth spin slowly, not faster? is it possible to prove it scientifically? can you prove it with math?

Brian made this table to organize his notes on changes of state change of state energy change melting gain freezing lose deposition gain condensation lose