Which is properly matched ?

Options

A. Echinodermata- Asteroidea- Starfish
B. Arthropoda-Insecta-Spider
C. Mollusca-Cephalopoda-Unio
D. Platyhelminthes-Trematoda-Planaria.

Answer

To determine which option is properly matched, we will analyze each option step by step.

### Step 1: Analyze the first option
- **Echinodermata - Asteroidae - Starfish**
- Echinodermata is a phylum that includes marine animals with a calcareous endoskeleton.
- Asteroidae is a class within Echinodermata that includes starfish.
- Starfish are indeed members of the Asteroidae class.

**Conclusion:** This option is correctly matched.

### Step 2: Analyze the second option
- **Arthropoda - Insecta - Spider**
- Arthropoda is a phylum that includes invertebrates with an exoskeleton.
- Insecta is a class within Arthropoda, but spiders belong to the class Arachnida.
- Therefore, the example given (spider) does not belong to the Insecta class.

**Conclusion:** This option is incorrectly matched.

### Step 3: Analyze the third option
- **Mollusca - Cephalopoda - Unio**
- Mollusca is a phylum that includes soft-bodied animals.
- Cephalopoda is a class within Mollusca, which includes animals like octopus and squids.
- Unio, commonly known as freshwater mussel, belongs to the class Bivalvia, not Cephalopoda.

**Conclusion:** This option is incorrectly matched.

### Step 4: Analyze the fourth option
- **Platyhelminth - Trematoda - Planaria**
- Platyhelminthes is a phylum that includes flatworms.
- Trematoda is a class within Platyhelminthes, which includes parasitic flatworms like liver flukes.
- Planaria belongs to the class Turbellaria, not Trematoda.

**Conclusion:** This option is incorrectly matched.

### Final Conclusion
After analyzing all the options, the only correctly matched option is:
- **Echinodermata - Asteroidae - Starfish**