Consider the following characters : Marine habitat , Statocyst, Cnidoblast, Colloblast cells, Comb plates, tentacles
How many characters are present in all adult ctenophores without any exception?

Options

A. Four
B. Five
C. Three
D. Six

Answer

To determine how many characters are present in all adult ctenophores without any exception, we will analyze each character listed in the question.

### Step-by-Step Solution:

1. **Marine Habitat**:
- Ctenophores are predominantly found in marine environments. This character is universally applicable to all adult ctenophores.
- **Hint**: Think about the natural environment where ctenophores are typically found.

2. **Statocyst**:
- Statocysts are balance organs found in some aquatic organisms, including some ctenophores. However, not all ctenophores possess statocysts, so this character cannot be considered universal for all adults.
- **Hint**: Consider whether this structure is present in every species of ctenophores.

3. **Cnidoblast**:
- Cnidoblasts, or stinging cells, are characteristic of cnidarians (like jellyfish and corals) but are not found in ctenophores. Instead, ctenophores have coloblasts. Therefore, this character does not apply to ctenophores.
- **Hint**: Recall the differences between ctenophores and cnidarians.

4. **Colloblast Cells**:
- Colloblasts are specialized cells found in ctenophores that help in capturing prey. This character is present in all adult ctenophores.
- **Hint**: Think about the function of these cells in the feeding mechanism of ctenophores.

5. **Comb Plates**:
- Comb plates are unique to ctenophores and are used for locomotion. However, not all species of ctenophores have comb plates, so this character cannot be considered universal for all adults.
- **Hint**: Consider if all ctenophores possess this structure.

6. **Tentacles**:
- Tentacles are present in all adult ctenophores and are used for capturing prey. This character is universal among them.
- **Hint**: Think about the role of tentacles in the feeding behavior of ctenophores.

### Conclusion:
After analyzing the characters, we find that the following four characters are present in all adult ctenophores without exception:
1. Marine habitat
2. Colloblast cells
3. Tentacles

Thus, the total number of characters present in all adult ctenophores is **4**.

### Final Answer:
**4**