Which of the following are correct ?
(i) Sponges :Cellular level of organization
(ii) Cnidaria : Tissue level of organization
(iii) Platyhelminthes :Organ level of organization
(iv) Annelids :Organ system level of organization .

Options

A. (ii) (iii) and (iv)
B. (i) (iii) and (iv)
C. (i) (ii) and (iii)
D. (i) , (ii) ,(iii)and (iv)

Answer

To determine which statements about the levels of organization in different animal phyla are correct, we can analyze each statement one by one:

1. **Sponges: Cellular level of organization**
- Sponges belong to the phylum Porifera. They are indeed characterized by a cellular level of organization, meaning their body is made up of specialized cells that perform different functions but do not form true tissues. Therefore, this statement is **correct**.

2. **Cnidaria: Tissue level of organization**
- Cnidarians, which include jellyfish, corals, and sea anemones, exhibit a tissue level of organization. This means they have specialized cells organized into tissues that perform specific functions. Thus, this statement is also **correct**.

3. **Platyhelminthes: Organ level of organization**
- Flatworms, which belong to the phylum Platyhelminthes, are indeed the first group of animals to exhibit an organ level of organization. They have organs that perform specific functions, making this statement **correct**.

4. **Annelids: Organ system level of organization**
- Annelids, such as earthworms and leeches, exhibit an organ system level of organization. This means they have complex systems (like the circulatory and digestive systems) that work together to perform various functions. Therefore, this statement is also **correct**.

After analyzing all four statements, we can conclude that all of them are correct.

### Final Conclusion:
- All four statements are correct. Therefore, the answer is that the fourth option (all of them) is correct.