Question

The circulatory system in annelids can be

Answer 1

Circulatory systems are of two types - open circulatory system and closed circulatory system.

In the open circulatory system, internal organs and body tissues are surrounded by circulatory fluid. Here, the circulatory fluid is pumped out of the heart and the cells and tissues directly bathe in it.

In a closed circulatory system the blood is circulated through a series of blood vessels of different diameters (arteries, veins and capillaries). Blood is contained inside blood vessels, circulating unidirectionally (in one direction) from the heart to the body, then returning to the heart again. In this way, blood is kept separate from body tissues. Circulatory system in annelids is generally of closed type but in some cases it can be open type also. For example, leeches.