Practise explaining why larger animals need hearts and mass transport systems to supply oxygen and glucose beyond diffusion limits.
The butterfly is an insect that feeds on nectar produced by flowers.
The photograph shows a butterfly feeding on a flower.
The circulatory system of an insect is described as an open system. This means that the blood is not contained inside blood vessels but flows through cavities called sinuses.
The diagram shows part of the circulatory system of an insect.
Conducting vessel: blood flows out of the
Explain why the circulation of a butterfly is different from the circulation of a mammal.