Which set of proteins is present in an inactive form in the blood but becomes activated via a cascade of events to play a role in immune responses?

A) complement
B) cytokine
C) interferon
D) lysozyme
E) prostaglandin

Complement

Set of proteins that circulate in inactive form in the blood; activated complement attracts phagocytes, coats antigenic particles, and punctures cells.

Immune Responses

The body's defensive mechanisms activated by the immune system to recognize and eliminate foreign substances or pathogens.