The lungs of the lung fish is an adaptation for respiration _______?

Analyze the question The question asks what the lungs of the lungfish are an adaptation for. Lungfish (e.g., Protopterus, the African lungfish found in Nigerian rivers and swamps) live in water but can survive out of water.

Explain the concept

• Lungfish have both gills and lungs (modified swim bladder).
• In water, they breathe mainly with gills.
• During the dry season, when water dries up, the lungfish burrows into mud and aestivates (a dormant state). The gills cannot work without water, so the lungs take over and let the fish breathe atmospheric air.

Solution

• Option A: complements gills in water. Lungs do supplement in oxygen-poor water, but this is not the main adaptation the question is looking for.
• Option B: complements gills on land. Gills do not function on land, since they collapse and dry out. So there is nothing for the lungs to complement.
• Option C: while on land. This is correct. The lungs are the organ that lets the lungfish breathe air when out of water or aestivating.
• Option D: while in water. The gills handle this primarily.

Answer: The lungs are the adaptation for respiration while on land (during drought/aestivation), which is option C.

Exam tip Remember: "Gills for water, lungs for land." Lungfish = "both lives": gills in the wet season, lungs in the dry season. Whenever you see lungfish, think aestivation and survival in drought.