CAIE IGCSE Biology 9.1.2 Single Circulation in Fish
Practise tracing blood from the fish heart through gills and body tissues before it returns to the heart.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise tracing blood from the fish heart through gills and body tissues before it returns to the heart.
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
Fig. 6.1 shows that fish and mammals have different types of circulation.
State why the fish circulation is called a single circulation.
blood passes through heart once in a complete circulation (of the body) ;
A in one circuit of the body