Final answer:
The colorless blood in the sinuses of arrow worms, specifically in the eosinophils granulocytes, serves several functions including fighting off parasites and regulating immune responses.
Step-by-step explanation:
The colorless blood in the sinuses of arrow worms, specifically in the eosinophils granulocytes, serves several functions. They release antihistamines and are especially active against parasitic worms.
Arrow worms, also known as chaetognaths, have a complex circulatory system with specialized cells called eosinophils. These cells contain granules that can be stained with eosin, a red dye.
The presence of colorless blood in the sinuses helps with various processes, such as fighting off parasites and regulating immune responses.