Which one of the following features is common to cockroach, earthworm and mosquito?

Options

A. Presence of chitinous exoskeleton
B. Presence of jointed appendages
C. Presence of two pair of wings
D. Presence of schizocoelom as a true coelom

Answer

To solve the question "Which one of the following features is common to cockroach, earthworm, and mosquito?", we will analyze the characteristics of each organism and identify the common feature among them.

### Step-by-Step Solution:

1. **Identify the Organisms**:
- Cockroach (Phylum: Arthropoda)
- Earthworm (Phylum: Annelida)
- Mosquito (Phylum: Arthropoda)

2. **Analyze Features of Each Organism**:
- **Cockroach**:
- Has an exoskeleton made of chitin.
- Possesses jointed appendages (legs).
- Has two pairs of wings.
- **Earthworm**:
- Has a segmented body.
- Lacks an exoskeleton; instead, it has a moist cuticle.
- Does not have wings or jointed appendages.
- **Mosquito**:
- Has an exoskeleton made of chitin.
- Possesses jointed appendages (legs and wings).
- Has two pairs of wings.

3. **Compare the Features**:
- The cockroach and mosquito share features typical of arthropods, such as an exoskeleton, jointed appendages, and wings.
- The earthworm, being an annelid, does not share these arthropod features but does have a true coelom (body cavity).

4. **Identify Common Features**:
- The only feature that is common to all three organisms (cockroach, earthworm, and mosquito) is the presence of a true coelom (as both the earthworm and cockroach possess this feature, while mosquitoes also have a body cavity).

5. **Conclusion**:
- Therefore, the common feature among cockroach, earthworm, and mosquito is the presence of a true coelom.

### Final Answer:
The common feature to cockroach, earthworm, and mosquito is the presence of a true coelom.