1. Briefly describe why the body’s defense system is divided into two types: innate defenses and adaptive defenses, i.e. what distinguishes the two types.

2. Briefly describe the antagonistic action of muscles in the arm that result in the up and down movement of the forearm.

3. Briefly describe the difference between a malignant tumor and a benign tumor.

4. Briefly describe the difference between a malignant tumor and a benign tumor.