Which statement is incorrect regarding human blood ?

Options

A. Average leucoytes count is 6000-8000 `mm^(-3)`
B. Average RBC count is 2-4 million `mm^(-3)`
C. Proteins contribute about 8 percent of plasma
D. A healthy human has about 12-16 gms of haemoglobin per 100 ml blood

Answer

To determine which statement is incorrect regarding human blood, we will analyze each of the provided statements step by step.

### Step 1: Analyze the first statement
**Statement:** The average leukocyte count is 6000 to 8000 per cubic millimeter.
- **Analysis:** This statement is correct. The normal range for leukocytes (white blood cells) is indeed between 6000 to 8000 cells per cubic millimeter of blood.

### Step 2: Analyze the second statement
**Statement:** The average RBC count is 2 to 4 million per cubic millimeter.
- **Analysis:** This statement is incorrect. The normal range for red blood cells (RBCs or erythrocytes) is approximately 5 to 5.5 million per cubic millimeter, not 2 to 4 million. Therefore, this statement is the one that is incorrect.

### Step 3: Analyze the third statement
**Statement:** The proteins contribute around 8% of the plasma.
- **Analysis:** This statement is correct. Proteins in blood plasma typically account for about 6 to 8% of the plasma volume, which makes this statement accurate.

### Step 4: Analyze the fourth statement
**Statement:** A healthy human will have around 12 to 16 grams of hemoglobin per 100 ml of blood.
- **Analysis:** This statement is also correct. The normal range for hemoglobin in healthy adults is indeed around 12 to 16 grams per 100 ml of blood, with slight variations between males and females.

### Conclusion
After analyzing all the statements, we find that the second statement regarding the average RBC count is incorrect.

**Final Answer:** The incorrect statement regarding human blood is that the average RBC count is 2 to 4 million per cubic millimeter.

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