Which of the following statements is correct ?

Options

A. Acquired immunity is pathogen specific
B. The exaggerated response of the immune system to certain antigens present in the environment is called Auto-immunity
C. Bone marrow acts as a filter of the blood by trapping blood borne micro-organisms.
D. AIDS is caused by a group of viruses called rhinovirus

Answer

To determine which statement is correct, let's analyze each option provided in the question step by step.

### Step 1: Analyze the first statement
**Statement:** Acquired immunity is pathogen-specific.

**Analysis:** Acquired immunity, also known as adaptive immunity, is indeed pathogen-specific. This means that the immune response is tailored to a specific pathogen, and the antibodies produced are specific to the antigens of that pathogen.

**Conclusion:** This statement is correct.

### Step 2: Analyze the second statement
**Statement:** The exaggerated response of the immune system to certain antigens present in the environment is called autoimmunity.

**Analysis:** Autoimmunity refers to the immune system mistakenly attacking the body's own cells, not an exaggerated response to environmental antigens. The exaggerated immune response to environmental antigens is known as an allergy or hypersensitivity.

**Conclusion:** This statement is incorrect.

### Step 3: Analyze the third statement
**Statement:** Bone marrow acts as a filter of the blood by trapping the blood-borne microorganisms.

**Analysis:** Bone marrow is primarily responsible for the production of blood cells, including red blood cells, white blood cells, and platelets. It does not function as a filter for blood-borne microorganisms; that role is typically associated with organs such as the spleen and lymph nodes.

**Conclusion:** This statement is incorrect.

### Step 4: Analyze the fourth statement
**Statement:** AIDS is caused by the group of viruses called rhinovirus.

**Analysis:** AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), not rhinovirus. Rhinoviruses are primarily responsible for the common cold.

**Conclusion:** This statement is incorrect.

### Final Conclusion
After analyzing all the statements, the only correct statement is the first one: "Acquired immunity is pathogen-specific."