When Did Ptolemy Live

question 59

Multiple Choice

When did Ptolemy live?

• A)about 5000 years ago
• B)about 2000 years ago
• C)about 1000 years ago
• D)about 500 years ago
• E)about 100 years ago

---

Definitions:

Immune System

The complex network of cells, tissues, and organs that work together to defend the body against infections, diseases, and foreign substances.

Antigens

Substances that provoke an immune response, leading to the production of antibodies as part of the body's defense against infections and diseases.

Cancer Cells

Abnormal cells that divide uncontrollably and may invade nearby tissues or spread to other parts of the body.

Antigen

A foreign invader of the body, such as a bacterium or virus.