Which of the following option is correct?

Options

A. Osteichthyes - 4 pairs of gill slits covered by operculum
B. Chondrichthyes - 6-15 pairs of gill slits
C. Arthropoda - Metamerism and excretion by nephridia
D. Platyhelminthes – Bilateral symmetry & coelomate e.g., Taenia and Fasciola

Answer

To determine which of the given options is correct, we will analyze each option one by one based on the information provided in the transcript.

### Step-by-Step Solution:

1. **Analyze Option 1: Austic These**
- The statement claims that Austic These have four pairs of gill slits covered by the upper column.
- This statement is **correct**. Austic These (which may refer to a specific group of aquatic animals) indeed possess four pairs of gill slits.

2. **Analyze Option 2: Chondrichthyes**
- The statement claims that Chondrichthyes have 16 to 15 pairs of gill slits.
- This statement is **incorrect**. Chondrichthyes (cartilaginous fish like sharks and rays) do not have 16 to 15 pairs of gill slits. Instead, they typically have 5 to 7 pairs of gill slits.

3. **Analyze Option 3: Arthropoda**
- The statement claims that metamerism is associated with excretion by nephridia.
- This statement is **incorrect**. In Arthropoda, excretion is primarily carried out by Malpighian tubules, not nephridia. Nephridia are associated with annelids.

4. **Analyze Option 4: Platyhelminthes**
- The statement claims that Platyhelminthes are coelomates, with examples being Tinea and Fasciola.
- This statement is **incorrect**. Platyhelminthes (flatworms) are actually acoelomate, meaning they lack a true coelom.

### Conclusion:
Based on the analysis of all options, the only correct statement is found in Option 1 regarding Austic These. Therefore, the correct answer is **Option 1**.

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