Having one theory is setting a limit on your potential and the potential of the overall theory and subject you are working on. Having multiple theories gives you a broader idea and perspective of what is going on, and even though one may slightly contradict the other, it is okay because that is what theories are for.
To the point, scientists usually have more than one theory so that they can gain a broader perspective on the matter and maybe even increase the chance of being correct on the matter.
Hope this was helpful.
Cheers,
Answer:
the answer would be botan (:
Plants produce oxygen that animals use for respiration
A nervous system because worms don't have nerves
Man i hate school that really makes my head hurt
