All of these are vertebrates EXCEPT

Step 1: Analyze the question We need the one animal that is NOT a vertebrate, meaning the one without a backbone (vertebral column).

Step 2: Concept Vertebrates are animals with a backbone. They fall into five classes:

• Fishes (Pisces)
• Amphibians
• Reptiles
• Birds (Aves)
• Mammals

Invertebrates have no backbone. Examples include insects, worms, snails, and echinoderms.

Step 3: Classify each option

• A. Lizard: a reptile, so it is a vertebrate.
• B. Rat: a mammal, so it is a vertebrate.
• C. Starfish: it belongs to Phylum Echinodermata. It has no backbone and is an invertebrate.
• D. Tilapia fish: a bony fish, so it is a vertebrate.
• E. Toad: an amphibian, so it is a vertebrate.

Step 4: Answer The starfish is the only invertebrate in the list, so the answer is C.

Exam tip: Remember that "fish" in a name does not make an animal a vertebrate. Starfish, jellyfish, and cuttlefish are all invertebrates, so watch out for these in JAMB, WASSCE, and NECO questions. Echinoderms (starfish, sea urchins) have spiny skin and tube feet, with no backbone.