An open circulatory system simply
means that the blood flows out of vessels and into the spaces or sinuses. Invertebrates,
insects and crustaceans has an open circulatory system where pump blood goes
into a hemocoel and diffusing back to the circulatory system between cells. In
other animals, the heart pumps the blood into the body cavities, spaces or
sinuses, where the blood surrounds the tissues.
If your immune system attacks your own body parts, then it's called 'autoimmune disease'.
Autoimmune disease can happen at many times due to many problems the body can have. If one thing goes wrong with your body, it can go to another.
I THINK!!! a. but i could be wrong sry if i am
