In man , the number of R.B.C. per cubic mm of blood is
(a) 1 to 3 millions
(b) 5 to 5.4 millions
(c) Less than one milliion but more than 50 thousand
(d) Less than 50 thousand

Options

A. 1 to 3 millions
B. 5 to 5.4 millions
C. Less than one milliion but more than 50 thousand
D. Less than 50 thousand.

Answer

To solve the question regarding the number of red blood cells (RBCs) per cubic mm of blood in a healthy adult man, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking for the normal range of red blood cells (RBCs) present in a cubic millimeter of blood in humans.

2. **Identify the Types of Blood Cells**: There are three main types of blood cells:
- Red Blood Cells (RBCs or erythrocytes)
- White Blood Cells (WBCs or leukocytes)
- Platelets (thrombocytes)

3. **Focus on RBCs**: The question specifically asks about RBCs, which are the most abundant type of blood cell in the human body.

4. **Know the Normal Range**: The average number of RBCs in a healthy adult male is typically between 5 to 5.4 million per cubic mm of blood.

5. **Evaluate the Options**:
- (a) 1 to 3 million: This range is lower than the normal count.
- (b) 5 to 5.4 million: This range matches the normal count for a healthy adult male.
- (c) Less than 1 million but more than 50 thousand: This range is also lower than the normal count.
- (d) Less than 50 thousand: This is significantly lower than the normal count.

6. **Select the Correct Answer**: Based on the information, the correct answer is (b) 5 to 5.4 million.

### Final Answer:
(b) 5 to 5.4 millions

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