Read the given statements and select the incorrect one.

Options

A. An exaggerated immune response on exposure to pollen, dust, etc., in some individuals is due to release of histamine and serotonin from mast cells.
B. Immunodeficiency diseases are due to failure of immune system to distinguish between self and nonself cells.
C. During HIV injection, RNA genome of virus replicates to form viral DNA which gives incorporated into host cell's DNA.
D. Cancer cells resist induction of cell death and promotes tumour development.

Answer

To solve the question regarding the incorrect statement, we will analyze each statement provided in the video transcript step by step.

### Step 1: Analyze the First Statement
The first statement discusses an exaggerated immune response to allergens like pollen and dust, which is due to the release of histamine and serotonin from mast cells. This statement is correct. Allergies are indeed characterized by such responses.

**Hint:** Allergies involve an exaggerated immune response to harmless substances.

### Step 2: Analyze the Second Statement
The second statement explains that the hypersensitive response of the immune system when exposed to foreign substances is called an allergy. This is also correct. Allergies are hypersensitive responses to typically harmless substances.

**Hint:** Hypersensitivity refers to an exaggerated immune response.

### Step 3: Analyze the Third Statement
The third statement mentions that immunodeficiency diseases result from the immune system's failure to distinguish between self and non-self cells. This is incorrect. Immunodeficiency diseases are characterized by a reduced immune response, while the inability to distinguish between self and non-self cells is a hallmark of autoimmune diseases.

**Hint:** Immunodeficiency relates to a weakened immune response, not misidentification of cells.

### Step 4: Analyze the Fourth Statement
The fourth statement discusses HIV and its replication process, stating that during HIV infection, the RNA genome of the virus replicates to form viral DNA. This is correct. HIV is an RNA virus that uses reverse transcriptase to convert its RNA into DNA.

**Hint:** HIV uses reverse transcriptase to convert RNA into DNA.

### Step 5: Analyze the Fifth Statement
The fifth statement describes cancer cells as resisting cell death and promoting tumor development. This is also correct. Cancer cells often evade normal regulatory mechanisms that lead to cell death, contributing to tumor growth.

**Hint:** Cancer cells have uncontrolled growth and resist apoptosis (programmed cell death).

### Conclusion
The incorrect statement among the options provided is the one regarding immunodeficiency diseases, as it incorrectly describes the nature of these diseases.

### Final Answer
The incorrect statement is: "Immunodeficiency diseases are due to the failure of the immune system to distinguish between self and non-self cells."