Which of the following are categorized under Chordata ?

Options

A. Urochordata and cephalochordate
B. Hemichordata and urochordata
C. Craniata and Hemichordata
D. Vertebrata and Echinodermata

Answer

To determine which of the given options are categorized under Chordata, we need to analyze each option based on the characteristics of Chordata. Chordates are defined by the presence of a notochord, a dorsal nerve cord, and pharyngeal gill slits at some stage of their development.

### Step-by-Step Solution:

1. **Understanding Chordata**:
- Chordates are animals that possess a notochord (a flexible rod-like structure), a dorsal hollow nerve cord, and pharyngeal gill slits at some point in their life cycle.

2. **Analyzing the Options**:
- **Option 1: Urochordata and Cephalochordata**:
- **Urochordata**: These are marine animals that have a notochord, a dorsal nerve cord, and gill slits during their larval stage.
- **Cephalochordata**: These also possess a notochord that extends from the brain to the tail, a dorsal nerve cord, and gill slits.
- **Conclusion**: Both groups belong to Chordata.

- **Option 2: Hemichordata and Urochordata**:
- **Hemichordata**: They have gill slits but lack a true notochord and dorsal nerve cord.
- **Urochordata**: As discussed, they belong to Chordata.
- **Conclusion**: Since Hemichordata does not meet the criteria, this option is incorrect.

- **Option 3: Craniata and Hemichordata**:
- **Craniata**: This group includes animals with a cranium (skull) and possesses a notochord, dorsal nerve cord, and gill slits.
- **Hemichordata**: As discussed, they do not possess all the features of Chordata.
- **Conclusion**: This option is incorrect due to Hemichordata.

- **Option 4: Vertebrata and Echinodermata**:
- **Vertebrata**: These are a subphylum of Chordata that possess a backbone, notochord, dorsal nerve cord, and gill slits.
- **Echinodermata**: These are invertebrates that do not possess a notochord or dorsal nerve cord.
- **Conclusion**: This option is incorrect due to Echinodermata.

3. **Final Conclusion**:
- The only option that contains groups fully categorized under Chordata is **Option 1: Urochordata and Cephalochordata**.

### Answer:
**Option 1: Urochordata and Cephalochordata** are categorized under Chordata.