Exams

Auto-immune disease :: Sometimes, due to genetic and other unknown reasons, the body attack self-cells. This results in damage to the body and is called auto-immune disease.

From the options,

-> Rheumatoid arthritis is an autoimmune disorder in which antibodies are produced against the synovial membrane and cartilage.

-> Vitiligo causes white patches on skin also characterised as autoimmune disorder.

-> Psoriasis is a skin disease that causes itchy or sore patches of thick red skin and is also autoimmune.

-> Alzheimer's disease is a chronic neurodegenerative disease. Alzheimer's disease is due to deficiency of neurotransmitter acetylcholine.

Hence, Alzheimer's is not the auto-immune disease.

The average propensity to consume (APC) is the ratio of consumption expenditures (C) to disposable income (DI), or APC = C / DI. 

Hence, APC = consumption/income.