Which statement best explains why invertebrates regenerate lost tissue more readily than most vertebrates do?
As compared to vertebrates, invertebrates have many more undifferentiated tissues and cells. This helps them to regenerate their tissues and even organs in case of injury or loss. It can be said that being simpler organisms has given them this advantage.
So, the correct answer is 'Invertebrates animals have more undifferentiated cells than vertebrate animals have.'