The immune system combats diseases ________.

A) by producing red blood cells, which engulf and kill pathogens
B) by generating antibodies, which attach themselves to antigens, deactivating them and marking them for destruction
C) by decreasing the flow of blood, cells, and natural chemicals to the damaged area, causing the redness, swelling, and warmth that characterize inflammation
D) by inhibiting endocrine and sympathetic activity

Immune System

The complex network of cells, tissues, and organs that work together to defend the body against attacks by foreign invaders, such as bacteria, viruses, and cancer cells.

Red Blood Cells

Blood cells responsible for carrying oxygen from the lungs to the body and carbon dioxide from the body to the lungs.

Antibodies

Proteins produced by the immune system to identify and neutralize foreign objects such as bacteria and viruses.