2025 · Q93
Which one of the following classes demonstrates double circulation of blood?
general-sciencebiology-human-body
- AInvertebrates
- BFishes
- CAmphibians
- DMammals
Explanation
Mammals (and birds) have a completely separated double circulation: the pulmonary circuit and the systemic circuit, with a four-chambered heart preventing mixing of oxygenated and deoxygenated blood. Fishes have single circulation and amphibians have incomplete double circulation. Hence mammals demonstrate double circulation.