2 major blood vessels
The earthworm like many more complex organisms has a closed circulatory system, meaning that its blood is confined to blood vessels and its blood is recirculated so it gets maximum use
Blood vessels can form new blood vessels, this is called angiogenesis.
Why are nephrons surrounded by many tiny blood vessels
How many kilometers of blood vessels are in your body? If they could be laid end to end, the blood vessels would cover a distance of about 60,000 miles (96,500 kilometers).
The heart is the main "container", along with the great vessels, such as the aorta and the vena cava as well as many of the other larger arteries and veins.
Earthworms have Red blood.
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3
There are three types of blood vessels. There are veins, arteries, and capillaries.
Diabetes is primarily a disease of blood vessels. Because blood vessels feed all our organs, many organs can be damaged when diabetes messes with the blood flow by damaging blood vessels. It's the constant high blood sugar in diabetics that damages blood vessels. If a diabetic keeps his blood sugar under control, it's as if he doesn't have the disease.
Marrow
it has two arteries along with a single vein