For a disease to develop in the body the correct sequence of components of immune system that should fail to work effectively are
A)Skin `to` Fever `to` B cells `to` antibodies `to` macrophage
B)Mucous membrane `to` NK cells `to` B cells `to` antibodies `to` T. cells
C) Tears `to` B cells `to` macrophages `to` antibodies to` saliva
D)Skin `to` inflammation`to` phagocytic cell `to` B cell `to` antibodies

Options

A. A
B. B
C. C
D. D

Answer

To determine the correct sequence of immune system components that should fail for a disease to develop, we need to analyze the options provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding the Immune Response**:
- The immune system has two main types of immunity: innate (non-specific) and adaptive (specific).
- The innate immune response includes physical barriers (like skin and mucous membranes), inflammation, and phagocytic cells (like macrophages).
- The adaptive immune response involves B cells and T cells, which produce antibodies and help in targeting specific pathogens.

2. **Analyzing Each Option**:
- **Option A**: Skin → Fever → B cells → Antibodies → Macrophage
- This sequence is incorrect because macrophages should respond before B cells and antibodies. The innate immune response (including macrophages) occurs before the adaptive response.

- **Option B**: Mucous membrane → NK cells → B cells → Antibodies → T cells
- This sequence is also incorrect. While NK cells are part of the innate immune response, the sequence does not include macrophages, which are crucial in the early response.

- **Option C**: Tears → B cells → Macrophages → Antibodies → Saliva
- This sequence is incorrect because it places B cells before macrophages. Macrophages are part of the innate immune response and should act before B cells are activated.

- **Option D**: Skin → Inflammation → Phagocytic cell → B cell → Antibodies
- This sequence is correct. It starts with the skin (a physical barrier), followed by inflammation (which recruits immune cells), then phagocytic cells (like macrophages) that engulf pathogens, and finally the activation of B cells leading to antibody production.

3. **Conclusion**:
- The correct sequence of immune system components that should fail for a disease to develop is **Option D**: Skin → Inflammation → Phagocytic cell → B cell → Antibodies.