Read the given statements about the blood vascular system of cockroach.
I. The circulatory system of cockroach is of closed type
II. It contains no blood vessels except aorta of the heart .
III. The heart is 6 - chambered.
IV The haemolymph is composed of coloruless plasma and haemocytes.
Which of the statement (s) given above is / are INCORRECT?
(a) only I
(b) I,II and III
(c) I and III
(d) only IV

Options

A. only I
B. I,II and III
C. I and III
D. only IV

Answer

To solve the question regarding the blood vascular system of cockroaches, we will analyze each statement one by one to determine which are incorrect.

### Step-by-Step Solution:

1. **Evaluate Statement I**:
- **Statement**: "The circulatory system of cockroach is of closed type."
- **Analysis**: The circulatory system of cockroaches is actually an open type, not a closed type. In an open circulatory system, blood (hemolymph) is not confined exclusively to vessels but flows freely in the body cavity.
- **Conclusion**: This statement is **incorrect**.

2. **Evaluate Statement II**:
- **Statement**: "It contains no blood vessels except aorta of the heart."
- **Analysis**: In cockroaches, there are no true blood vessels; the only vessel-like structure is the aorta, which is part of the heart. The hemolymph circulates freely in the body cavity.
- **Conclusion**: This statement is **correct**.

3. **Evaluate Statement III**:
- **Statement**: "The heart is 6-chambered."
- **Analysis**: The heart of a cockroach is actually 13-chambered, not 6-chambered. Each chamber helps in pumping the hemolymph throughout the body.
- **Conclusion**: This statement is **incorrect**.

4. **Evaluate Statement IV**:
- **Statement**: "The hemolymph is composed of colorless plasma and haemocytes."
- **Analysis**: Hemolymph in cockroaches does consist of a colorless fluid (plasma) and cells known as hemocytes. The absence of hemoglobin gives it a colorless appearance.
- **Conclusion**: This statement is **correct**.

### Summary of Findings:
- **Incorrect Statements**: I (closed type) and III (6-chambered).
- **Correct Statements**: II (no blood vessels except aorta) and IV (hemolymph composition).

### Final Answer:
The incorrect statements are I and III. Therefore, the correct option is **(c) I and III**.

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