Which of these statements is not true about cockroaches ?

Options

A. Cockroaches have an endoskeleton made of chitin which spans the whole body
B. The body of the cockroach can be divided into three parts - head , thorax and abdomen
C. Head is made of six fused segments
D. The mouth consists of chitinous mouth parts.

Answer

To determine which statement is not true about cockroaches, we need to analyze the provided statements one by one.

1. **Cockroaches come under the phylum Arthropoda.**
- This statement is true. Cockroaches belong to the phylum Arthropoda, which includes invertebrates with an exoskeleton, segmented bodies, and jointed appendages.

2. **Cockroaches have an endoskeleton made up of chitin.**
- This statement is not true. Cockroaches have an exoskeleton made of chitin, not an endoskeleton. An endoskeleton is found in organisms like mammals, where the skeleton is internal.

3. **The body of a cockroach can be divided into three parts.**
- This statement is true. The body of a cockroach is divided into three main parts: the head, thorax, and abdomen.

4. **The head is made up of six fused segments.**
- This statement is true. The head of a cockroach consists of six fused segments, and it contains various structures including the mouthparts, which are also made of chitin.

5. **The mouth consists of chitinous mouth parts.**
- This statement is true. The mouthparts of a cockroach are indeed made of chitin, which is a tough, protective protein.

Based on the analysis, the statement that is not true about cockroaches is: **"Cockroaches have an endoskeleton made up of chitin."**

### Step-by-Step Solution:
1. Identify the phylum to which cockroaches belong.
- Cockroaches belong to the phylum Arthropoda.

2. Examine the type of skeleton cockroaches possess.
- Cockroaches have an exoskeleton made of chitin, not an endoskeleton.

3. Confirm the division of the cockroach body.
- The body is divided into three parts: head, thorax, and abdomen.

4. Analyze the structure of the head.
- The head consists of six fused segments.

5. Check the composition of the mouthparts.
- The mouthparts are made of chitin.

6. Conclude which statement is false.
- The false statement is that cockroaches have an endoskeleton made of chitin.