1. Which of the following characteristics is shared by all insects?
a) Two pairs of wings
b) Three pairs of legs
c) A soft, segmented body
d) A simple eye structure
Answer: b) Three pairs of legs
Explanation: All insects belong to the class Insecta, and one of their defining characteristics is having three pairs of legs, which distinguishes them from other arthropods.
2. What is the term used to describe the shedding of the exoskeleton in insects?
a) Metamorphosis
b) Molting
c) Ecdysis
d) Pupation
Answer: c) Ecdysis
Explanation: Ecdysis is the process of shedding or molting the exoskeleton in insects to allow for growth. It is a necessary part of their development.
3. Which of the following is an example of an insect that undergoes complete metamorphosis?
a) Grasshopper
b) Termite
c) Butterfly
d) Silverfish
Answer: c) Butterfly
Explanation: Insects that undergo complete metamorphosis have four distinct stages: egg, larva, pupa, and adult. Butterflies are an example, while grasshoppers, termites, and silverfish undergo incomplete metamorphosis.
4. In the context of insect physiology, what is the main function of the Malpighian tubules?
a) Respiration
b) Excretion of metabolic wastes
c) Circulation of hemolymph
d) Digestion of food
Answer: b) Excretion of metabolic wastes
Explanation: The Malpighian tubules are the excretory organs in insects, responsible for removing metabolic wastes from the insect’s body and maintaining water balance.
5. Which of the following orders of insects contains species that are primarily decomposers?
a) Coleoptera (beetles)
b) Lepidoptera (butterflies and moths)
c) Diptera (flies)
d) Isoptera (termites)
Answer: a) Coleoptera (beetles)
Explanation: Many species of beetles, especially within the families Scarabaeidae and Tenebrionidae, are decomposers and play a critical role in breaking down organic matter in ecosystems.
6. Which of the following insect adaptations helps in avoiding desiccation (water loss) in arid environments?
a) Development of wings
b) Thickened exoskeleton
c) Malpighian tubules
d) Sclerotization of cuticle
Answer: b) Thickened exoskeleton
Explanation: Insects living in arid environments often have thickened exoskeletons, which help minimize water loss and protect against desiccation.
7. In which stage of complete metamorphosis does an insect undergo physiological reorganization to form the adult form?
a) Egg
b) Larva
c) Pupa
d) Adult
Answer: c) Pupa
Explanation: During the pupal stage of complete metamorphosis, the insect undergoes significant physiological changes, transforming from the larval form into the adult form.
8. Which of the following is a primary characteristic of insects in the order Hemiptera?
a) Chewing mouthparts
b) Wingless adults
c) Sucking mouthparts
d) Complex metamorphosis
Answer: c) Sucking mouthparts
Explanation: Hemiptera, commonly known as true bugs, are characterized by their piercing-sucking mouthparts, which they use to feed on plant sap or animal fluids.
9. Which structure in insects is primarily responsible for gas exchange?
a) Heart
b) Tracheae
c) Digestive system
d) Malpighian tubules
Answer: b) Tracheae
Explanation: Insects use a system of tracheae (tubes) to facilitate gas exchange, directly delivering oxygen to tissues and removing carbon dioxide, bypassing the need for a circulatory system to transport gases.
10. Which of the following is a characteristic feature of insects in the order Diptera (flies)?
a) Two pairs of wings
b) One pair of wings and halteres
c) Four wings with a membranous structure
d) Scaly wings
Answer: b) One pair of wings and halteres
Explanation: Flies (Diptera) are characterized by having a single pair of wings, with a second pair of wings modified into small balancing organs called halteres.
11. Which of the following is true regarding the insect’s circulatory system?
a) It is a closed circulatory system like in vertebrates
b) Hemolymph is circulated to all body parts by a heart that pumps through vessels
c) Oxygen is carried by the blood, similar to the hemoglobin system in humans
d) The circulatory system plays a major role in nutrient absorption
Answer: b) Hemolymph is circulated to all body parts by a heart that pumps through vessels
Explanation: Insects have an open circulatory system where the hemolymph (insect blood) is pumped by a heart through vessels to bath organs directly, providing nutrients and waste removal.
12. What is the term used to describe the process by which an insect changes its body form dramatically during its life cycle?
a) Ecdysis
b) Metamorphosis
c) Mating
d) Copulation
Answer: b) Metamorphosis
Explanation: Metamorphosis is the process of developmental changes that insects undergo, which can be either complete (with egg, larva, pupa, and adult stages) or incomplete (with egg, nymph, and adult stages).
13. Which insect order contains species that exhibit the longest lifespan among insects?
a) Coleoptera (beetles)
b) Lepidoptera (moths and butterflies)
c) Hymenoptera (ants, bees, and wasps)
d) Odonata (dragonflies)
Answer: c) Hymenoptera (ants, bees, and wasps)
Explanation: Some species of ants, bees, and wasps, particularly queens, can live for several years, making them among the longest-lived insects.
14. What is the primary role of the insect exoskeleton?
a) Nutrient absorption
b) Protection against predators and environmental stress
c) Respiration
d) Facilitation of movement
Answer: b) Protection against predators and environmental stress
Explanation: The exoskeleton provides structural support, protects the insect from predators, desiccation, and environmental factors, and also acts as a barrier to pathogens.
15. Which of the following is an example of an insect that has a symbiotic relationship with plants?
a) Mosquitoes
b) Termites
c) Pollinating bees
d) Houseflies
Answer: c) Pollinating bees
Explanation: Pollinating bees form a symbiotic relationship with plants by transferring pollen from one flower to another, aiding in plant reproduction, while they collect nectar for their own nourishment.