1) cells are the smallest units of life
2) living organisms are made up of cells
3) all cells come from existing cells
Answer:
The circulatory system of the crayfish is an open system where the blood is contained in vessels for only part of the system. The heart is located in a pericardial sinus located in the upper part of the thorax (a sinus is a sac or cavity). The heart pumps the blood into the arteries.
Explanation:
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