Foreign substances in the body that provoke an immune response are called:

• A. lysozymes
• B. cytokines
• C. antigens
• D. antibodies

Answer: (C)

Verified step by step guidance

1. Understand the key terms involved in the problem: lysozymes, cytokines, antigens, and antibodies.
2. Recall that lysozymes are enzymes that break down bacterial cell walls and are part of the innate immune system, not substances that provoke immune responses.
3. Recognize that cytokines are signaling molecules that help regulate immune responses but are not foreign substances themselves.
4. Know that antibodies are proteins produced by the immune system to specifically bind to foreign substances, but they are not the foreign substances themselves.
5. Identify that antigens are foreign substances (such as parts of pathogens) that trigger the immune system to respond, making 'antigens' the correct term for substances provoking an immune response.