Question

Which one of the following invertebrates has the most primitive visual system?

• A. Ammonites
• B. Brachiopods
• C. Gastropods
• D. Trilobites

Hint:

Trilobites are known for their compound eyes, which are considered primitive compared to modern visual systems.

Answer 1

The Correct Option is D

Step 1: Understanding the visual systems of invertebrates.
The visual systems of invertebrates vary greatly. Some invertebrates, such as trilobites, had simple eyes known as compound eyes, which are considered primitive compared to the more advanced visual systems found in other invertebrates.

Step 2: Analyzing the options.
(A) Ammonites: Ammonites had highly developed eyes, with complex lenses, much more advanced than trilobites.
(B) Brachiopods: Brachiopods have simple visual structures or none at all, but not the most primitive compared to trilobites.
(C) Gastropods: Gastropods have complex eyes with lenses and retinas, more advanced than trilobites.
(D) Trilobites: This is the correct answer. Trilobites had compound eyes, considered one of the most primitive visual systems in the animal kingdom.

Step 3: Conclusion.
The correct answer is (D) Trilobites because they had the most primitive visual system among the options provided.