Some autoimmune disorders are thought to be caused by , which occurs when an infectious agent is composed of antigens with the same amino acid sequences as the body's self antigens, resulting in the immune system attacking normal tissue with the similar composition.

adaptive immune response

Explanation:

Autoimmune disorders are caused by different microoorganism and drug which manipulates the immune system in a way that immune system become unable to recognise between self antigen and foreign antigen. In that case immune system treats foreign antigen as self antigen which cause systemic or organ specific damage.

The exact cause of autoimmune disorders is unknown and hence it is  thought that it is caused by adaptive immune response which builds against self antigens and causes damage to the cells.

Hence, some autoimmune disorders are thought to be caused by adaptive immune response.

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.

sadness is not good

explanation: