I agree animals are used for commercial or scientific purpose.
The animals have similar respiratory and digestive tract of humans and the creature all over the world.
Most similar to man breathing or have the highest probability to success for the test because through their digestive systems. ​ we can prevent or cure many diseases through.
What kind of medicine or treatment of performance, functionality, can find out about side effects in advance.
Occasionally, some animal experiments, but I used to brutal and cruel.
Nowadays, many countries and organizations to reduce the pain of animals.
Three laws or rules, such as 3r.
3r is replacement, reduction, refinement.
Find a way that could replace animal testing if these animal experiments and should be replaced.
And minimize the number of animals used in experiments.
Pain should be reduced as much as possible the rules of the animals in the experiment.
Let me put it this way animal ​ if enacted several laws for the rights.
Brutality or cruelty to prevent or reduce animal testing.