CAIE IGCSE Biology 9.1.4 Advantages of Double Circulation
Practise explaining how separate circuits deliver oxygenated blood to body tissues rapidly and at suitable pressure.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise explaining how separate circuits deliver oxygenated blood to body tissues rapidly and at suitable pressure.
Fig. 6.1 shows diagrams of the circulatory systems of a fish and a mammal.
The arrows show the direction of blood flow through the circulatory systems.

Fig. 6.1
Explain the advantages of the double circulation of the mammal.
any three from:
1 efficient / AW, supply of, blood / oxygen / nutrients (to, body / AW) ;
2 efficient / AW, removal of, carbon dioxide / urea / wastes (from body / AW) ;
3 low(er) pressure in, pulmonary, artery / circuit / AW ;
4 to prevents damage to (capillaries in the) lungs ;
5 allows more time for gas exchange ;
6 allows high(er) pressure (in body) ;
7 to allow efficient, filtration in kidneys (for excretion) ;
8 to allow / maintain, a high, metabolic rate / rate of respiration ;
9 AVP ;
MP8 A allows a high(er) body temperature / maintains body temperature
MP9 e.g. larger / steeper, diffusion gradient between
capillaries and respiring tissues OR allows large body
size