The term 'active immunity' means

Options

A. resistance developed before disease
B. resistance developed after disease
C. increased heart beat
D. increased flow of blood

Answer

### Step-by-Step Solution:

1. **Understanding Immunity**: Begin by recognizing that immunity is the body's ability to resist infections and diseases. There are two main types of immunity: active and passive immunity.

2. **Definition of Active Immunity**: Active immunity refers to the process where the body produces its own antibodies in response to an antigen. This can occur naturally when the body is exposed to a pathogen, or artificially through vaccination.

3. **Mechanism of Active Immunity**: When an antigen enters the body (either through infection or vaccination), the immune system recognizes it as foreign. This triggers the immune response, leading to the production of antibodies specific to that antigen.

4. **Role of Memory Cells**: After the initial exposure to the antigen, the immune system creates memory cells. These cells "remember" the specific antigen, allowing for a quicker and more effective response if the body encounters the same pathogen again in the future.

5. **Timing of Resistance Development**: It is important to note that active immunity develops after exposure to the antigen, either through natural infection or vaccination. This means the body does not have immediate resistance before encountering the disease.

6. **Conclusion**: Therefore, the term 'active immunity' means the immunity that is developed by the body through the synthesis of antibodies in response to antigens, leading to long-lasting protection due to the presence of memory cells.