In adult urochordate, lateral line system is absent because

Options

A. They are predator
B. They have ampullae of Lorenzini
C. They are sedentary
D. They show progressive metamorphosis Retrogressive metamorphosis is the feature of

Answer

### Step-by-Step Solution:

1. **Understanding Urochordates**: Urochordates, also known as tunicates, are marine animals that exhibit a notochord in their larval stage. As they mature into adults, they undergo significant changes, including the loss of certain features.

2. **Defining the Lateral Line System**: The lateral line system is a sensory organ found in many aquatic animals, which helps in detecting movement and vibrations in the surrounding water. It is particularly important for predators and active swimmers.

3. **Characteristics of Adult Urochordates**: Adult urochordates are primarily sedentary, meaning they are fixed in one position and do not actively swim or hunt like their larval forms. This lifestyle significantly influences their sensory adaptations.

4. **Reason for Absence of Lateral Line System**: Since adult urochordates are sedentary and do not need to detect movement in their environment for hunting or navigation, the lateral line system becomes unnecessary. They rely on other sensory adaptations, such as the ampulla of Lorenzini, for detecting environmental changes.

5. **Conclusion**: Therefore, the absence of the lateral line system in adult urochordates can be attributed to their sedentary nature, which eliminates the need for this sensory system.