Select the mismatch from the following

Options

A. Helix - Organ system level of organization
B. Asterias - Presence of water vascular system
C. Neries - Excretion by flame cells
D. Eye worm - Pseudocoelomate

Answer

To solve the question of identifying the mismatch among the given options, we will analyze each option step by step.

### Step 1: Analyze the first option - Helix and organ system level of organization
- **Helix** refers to the helical structure of DNA.
- DNA is indeed a fundamental molecule that contributes to the structure and function of living organisms.
- The organ system level of organization refers to how different organs work together to form systems in multicellular organisms.
- Since DNA is crucial for the development of organs and systems, this match is **correct**.

### Step 2: Analyze the second option - Asterias and water vascular system
- **Asterias** is a genus of starfish, which belongs to the phylum Echinodermata.
- Echinoderms are known for their unique water vascular system, which is used for locomotion, feeding, and gas exchange.
- Therefore, this match is also **correct**.

### Step 3: Analyze the third option - Nereus and excretion by flame cells
- **Nereus** refers to a genus within the phylum Annelida, which includes segmented worms.
- In Annelids, the excretory organs are called nephridia, not flame cells.
- Flame cells are specialized excretory cells found in flatworms (phylum Platyhelminthes).
- Therefore, this match is **incorrect**.

### Step 4: Analyze the fourth option - Eye worm and pseudocoelomate
- **Eye worm** (Loa loa) is a type of parasitic worm that belongs to the phylum Nematoda (roundworms).
- Nematodes are indeed pseudocoelomates, meaning they have a body cavity that is not completely lined by mesoderm.
- Thus, this match is **correct**.

### Conclusion
The mismatch in the options provided is the third option: Nereus excretion by flame cells. Nereus should be associated with nephridia, not flame cells.

### Final Answer
The mismatch is: **Nereus excretion by flame cells**.

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