Correct Option
The correct option is Insects.
Explanation
Respiratory organs vary among different groups of animals depending on their habitat and level of organization. The tracheal system is a specialized network of air tubes used for direct gas exchange in certain terrestrial invertebrates.
Option Analysis
- Insects Insects: Correct. Insects respire through a network of tubes known as tracheal tubes. These tubes open to the exterior through small openings called spiracles, allowing atmospheric air to reach tissues directly. This system is characteristic of the class Insecta within the phylum Arthropoda.
- Earthworms Earthworms: Incorrect. Earthworms use their moist cuticle (skin) for gas exchange. This mode of respiration is termed cutaneous respiration.
- Fishes Fishes: Incorrect. Fishes and most aquatic arthropods use gills for respiration. This is known as branchial respiration, which is adapted for extracting oxygen dissolved in water.
- Sponges Sponges: Incorrect. Lower invertebrates like sponges, coelenterates, and flatworms exchange oxygen and carbon dioxide by simple diffusion over their entire body surface. They lack specialized respiratory organs.
Key Takeaway
Insects utilize a system of tracheal tubes for respiration. In contrast, earthworms rely on moist skin (cutaneous), fishes rely on gills (branchial), and lower invertebrates like sponges rely on simple diffusion.