Answer the following question given this paragraph: 

Most flatworms have a distinct head region that includes nerve cells and sensory organs, such as eyespots. The development of a head region, called cephalization , evolved at the same time as bilateral symmetry in animals. This process does not occur in cnidarians, which evolved prior to flatworms and have radial symmetry.


Q: The development of a head region is called what?

 Choices:

- trichina

- spore

- cocklebur

- cephalization

A:
cephalization
