Question

Study the following and identify the correct statements.
• In cockroach, sub-oesophageal ganglion is the principal sensory centre.
• Ventral nerve cord of cockroach has only nine ganglia along its length.
• The images formed by ommatidia in nocturnal insects are called superposition images.
• During expiration, thoracic spiracles are kept open and abdominal spiracles are kept closed in cockroach.

• A. II, IV
• B. I, II
• C. III, IV
• D. I, IV

Hint:

Remember: \[ \boxed{ \begin{aligned} &\text{Supra-oesophageal ganglion} \rightarrow \text{Principal sensory centre} &\text{Nocturnal insects} \rightarrow \text{Superposition image} &\text{Diurnal insects} \rightarrow \text{Apposition image} \end{aligned} } \]

Answer 1

The Correct Option is C

Step 1: Examine each statement. \[ \begin{aligned} I. &\text{False} &&\text{Supra-oesophageal ganglion is the principal sensory centre.} II. &\text{False} &&\text{Ventral nerve cord has } \boxed{9\text{ thoracic and abdominal ganglia + sub-oesophageal ganglion}.} III. &\text{True} &&\text{Nocturnal insects form superposition images.} IV. &\text{True} &&\text{During expiration, thoracic spiracles open while abdominal spiracles remain closed.} \end{aligned} \]

Step 2: Identify the correct statements. The correct statements are \[ \boxed{\text{III and IV}.} \]

Step 3: Choose the correct option. Hence, \[ \boxed{(C)} \] is the correct answer.