The Correct Answer is Option C - Radial Symmetry

Explanation:

Organisms attached to the substratum, such as sponges and sea anemones, often possess radial symmetry. Radial symmetry is a type of body symmetry in which the body parts are arranged around a central axis, similar to the spokes of a bicycle wheel. This arrangement allows the organism to interact with its environment in a more efficient manner.

Advantages of Radial Symmetry:

1. Efficient Capture of Food: Radially symmetrical organisms often have tentacles or other structures radiating out from their central axis. These structures can be used to capture food particles from the surrounding water. The radial arrangement allows for a greater surface area for food capture, increasing the chances of capturing prey.

2. Increased Sensory Perception: The radial symmetry also allows these organisms to have sensory organs (such as eyes or sensory tentacles) distributed in a circular pattern around their body. This arrangement provides a wider field of view, allowing them to detect predators or prey from multiple directions.

3. Improved Water Circulation: Many radially symmetrical organisms have cilia or other structures on their surface that create water currents. These currents help in the circulation of water and the exchange of gases and nutrients. This is especially important for sessile organisms that rely on water flow to bring in food and oxygen and remove waste.

4. Adaptability: Radial symmetry allows these organisms to respond to changes in their environment from any direction. They can orient themselves towards or away from a stimulus, increasing their chances of survival.

Examples of Radially Symmetrical Organisms:

- Cnidarians: Organisms like jellyfish, sea anemones, and corals possess radial symmetry. They have tentacles arranged in a circular pattern around their mouth.

- Echinoderms: Organisms like starfish, sea urchins, and sea cucumbers also display radial symmetry. They have arms or tube feet arranged radially around their central body.

In conclusion, the possession of radial symmetry in organisms attached to the substratum allows for efficient food capture, improved sensory perception, better water circulation, and adaptability to changing environmental conditions.

The organisms attached to the substratum possess radial symmetry in all vertical planes. All the animals belonging to cnidaria (e.g. jellyfish) and echinodermata (e.g. starfish) are radially symmetrical and typically sessile in their adult form. In radial symmetry the parts in an organ or organism when cut through the centre in any direction produces two halves that are mirror images of each other.