An organism that exhibits cephalization probably also _____.

• A. lacks a nervous system
• B. is sessile as an adult
• C. has bilateral symmetry
• D. is radially symmetrical

Answer: (C)

Verified step by step guidance

1. Understand the concept of cephalization: Cephalization refers to the concentration of sensory organs and nervous system structures at the anterior (head) end of an organism. This adaptation is typically associated with organisms that actively move and interact with their environment.
2. Review the relationship between cephalization and symmetry: Cephalization is strongly linked to bilateral symmetry, where the body can be divided into two mirror-image halves along a single plane. This symmetry allows for directional movement and the development of a head region.
3. Eliminate incorrect options: Organisms that lack a nervous system cannot exhibit cephalization, as it requires a centralized nervous system. Sessile organisms (those that are fixed in one place) generally do not exhibit cephalization because they do not need a head for active movement or environmental interaction. Radially symmetrical organisms, like jellyfish, do not have a distinct head region and thus do not exhibit cephalization.
4. Identify the correct answer: Organisms with cephalization are typically bilaterally symmetrical, as this body plan supports the development of a head and directional movement.
5. Conclude the reasoning: Cephalization is an evolutionary adaptation seen in bilaterally symmetrical organisms, enabling them to better sense and respond to their environment through a centralized nervous system and sensory organs located in the head region.