Aging of the immune system makes older people more susceptible to cancer and infectious disease because of a decline in ________.

A) alpha and beta globulins
B) red blood cells and platelets
C) complement proteins
D) prothrombin and fibrinogen
E) antigen-presenting cells and helper T cells

Immune System

A complex network of cells, tissues, and organs that work together to defend the body against pathogens and diseases.

Antigen-presenting Cells

Specialized cells of the immune system that process and present antigens to T-cells, initiating an immune response.

Helper T Cells

A type of T cell that plays an important role in the immune system by helping activate B cells to secrete antibodies and macrophages to destroy ingested microbes.