Cephalization, the clustering of neurons and interneurons in the anterior part of the animal, is apparent in cephalization, the clustering of neurons and interneurons in the anterior part of the animal, is apparent in hydra. sea stars. cnidarians. planaria.

Planaria.

Explanation:

The kingdom eukarys is divided into the different phyla including almost all the animals. The organism are classified on the basis of their level organisation, cavity and on the basis of coelom.

The cephalization is initial process for the deposition of nervous tissue in brain. The cephalization is absent in porifera and coelenterate.  The planaria also known as flat worms shows the process of cephalization and this process becomes more complex in higher animals.

Thus, the correct answer is option (4).

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.