Select the correct statement

Options

A. Rheumatoid arthritis is an example auto immune disease.
B. Body secretions lack antibodies
C. Genetic material of HIV is ds DNA
D. Spleen is a primary lymphoid organ

Answer

To solve the question "Select the correct statement," we will evaluate each of the provided options one by one.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- The statement is: "Rheumatoid arthritis is an example of autoimmune disorder."
- **Analysis:** Rheumatoid arthritis is indeed classified as an autoimmune disorder where the immune system mistakenly attacks the joints, leading to inflammation and pain.
- **Conclusion:** This statement is **correct**.

2. **Evaluate the Second Statement:**
- The statement is: "Body secretion lacks antibodies."
- **Analysis:** This statement is incorrect because body secretions, such as saliva, tears, and mucus, contain antibodies that help in the immune response by targeting antigens.
- **Conclusion:** This statement is **incorrect**.

3. **Evaluate the Third Statement:**
- The statement is: "Genetic material of HIV is double-stranded DNA."
- **Analysis:** This statement is also incorrect. The genetic material of HIV (Human Immunodeficiency Virus) is actually single-stranded RNA, not double-stranded DNA.
- **Conclusion:** This statement is **incorrect**.

4. **Evaluate the Fourth Statement:**
- The statement is: "Spleen is the primary lymphoid organ."
- **Analysis:** This statement is incorrect as well. The spleen is classified as a secondary lymphoid organ. Primary lymphoid organs include the bone marrow and thymus, where lymphocytes are produced and mature.
- **Conclusion:** This statement is **incorrect**.

### Final Conclusion:
After evaluating all the options, the only correct statement is the first one: "Rheumatoid arthritis is an example of autoimmune disorder."