This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Entomology, Subject name: Social & Preventive Medicine
Which stage of larva of housefly is voracious feeder - 
Select and explain. 
A. 1, B. 2, C. 3, D. 4
A: 1
Answer: A: 1 
Explanation: Ans. is 'a' i.e., 1 o The larva of housefly (maggot) moults twice, i.e. there are three instar stages,o The first instar larva is a varacious feeder, feeding mainly on decomposing liquid organic matter.