Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?

In complex multicellular organisms, specialized cells make up tissues, tissue makes up organs, organs make up organ systems and finally, organ systems make up organisms.
Since complex multicellular organisms have a very high degree of organization in their body, they cannot be reproduced from their cut body parts by the process of regeneration.
For example, a dog is a complex multicellular organism that cannot be regenerated from its cut body part say, a cut tail. This is because the cells present in the cut tail of a dog cannot produce the dog’s organs like the heart, brain, lungs, stomach, intestines limbs, etc. needed for the making of a complete dog.

Chapter 7