Apis, Bombyx , Culex and Limulus belongs to

Options

A. the largest phylum of animalia
B. the smallest group of animalia
C. the second-largest animal phylum
D. the animals have an endoskeleton of calcareous ossicles

Answer

To solve the question "Apis, Bombyx, Culex, and Limulus belong to which group?", we can follow these steps:

### Step 1: Identify the Organisms
- **Apis**: This is the genus for honey bees.
- **Bombyx**: This refers to the silkworm, specifically Bombyx mori.
- **Culex**: This is a genus of mosquitoes.
- **Limulus**: This refers to the horseshoe crab.

### Step 2: Determine the Classification of Each Organism
- All four organisms belong to the phylum **Arthropoda**.
- **Apis** (honey bee) is an insect.
- **Bombyx** (silkworm) is also an insect.
- **Culex** (mosquito) is another insect.
- **Limulus** (horseshoe crab) is a marine arthropod, specifically a member of the class Merostomata.

### Step 3: Analyze the Options
1. **Largest Phylum of Animalia**: This is **Arthropoda**, which includes insects, arachnids, crustaceans, and more.
2. **Smallest Group of Animalia**: This is incorrect; the smallest group is **Placozoa**.
3. **Second Largest Animal Phylum**: This is **Mollusca**, which is also incorrect for this question.
4. **Animals with Endoskeleton of Calcareous Ossicles**: This describes **Echinoderms**, which does not apply here.

### Step 4: Conclusion
Based on the classification and analysis, the correct answer is that **Apis, Bombyx, Culex, and Limulus belong to the phylum Arthropoda**.

### Final Answer
**Option 1: Arthropoda**

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