Which of the following statement is incorrect?

A. Platyhelminthes has incomplete digestive system.

B. In coelenterates, the arrangement of cells is more complex.

C. Nereis is monoecious but earthworms and leeches are dioecious.

D. Simple and compound eyes are present in the animals of those phylum whose over two-thirds of all named species on earth are arthropods.

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