Largest number of species occurs in the phylum

Options

A. Annelida
B. Echinodermate
C. Arthropoda
D. Coelenterata.

Answer

To determine which phylum has the largest number of species, we can analyze the options provided:

1. **Annelida**: This phylum has approximately 9,000 species.
2. **Echinodermata**: This phylum contains around 7,000 species.
3. **Arthropoda**: This phylum boasts an estimated 5 to 10 million species, which accounts for about 80% of all non-vertebrate animal species. The majority of species within this phylum belong to the class Insecta, which alone has about 5 million species.
4. **Selenitata**: This phylum has roughly 11,000 species.

Now, let's summarize the findings:

- Annelida: ~9,000 species
- Echinodermata: ~7,000 species
- Arthropoda: ~5 to 10 million species
- Selenitata: ~11,000 species

From this analysis, it is clear that the phylum with the largest number of species is **Arthropoda**, with an estimated 5 to 10 million species.

**Final Answer**: The largest number of species occurs in the phylum **Arthropoda**.

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