Which one of the following is correct?

Options

A. Plasma = Blood-Lymphocytes
B. Serum= Blood + Fibrinogen
C. Lymph = Plasma + RBC + WBC
D. Blood = Plasma + RBC + WBC + Platelets

Answer

To determine which of the given options is correct, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Analyze the First Option:**
- **Statement:** Plasma is equal to blood minus lymphocyte.
- **Evaluation:** This statement is incorrect. Plasma is the liquid component of blood that contains water, proteins, nutrients, hormones, and waste products, but it does not equate to blood minus lymphocytes. Lymphocytes are a type of white blood cell found in blood, but they are not the only cellular component.

2. **Analyze the Second Option:**
- **Statement:** Serum is equal to blood plus fibrinogen.
- **Evaluation:** This statement is also incorrect. Serum is the liquid that remains after blood has clotted and does not contain fibrinogen, which is a protein necessary for blood clotting. Therefore, serum cannot be defined as blood plus fibrinogen.

3. **Analyze the Third Option:**
- **Statement:** Lymph is equal to plasma, red blood cell, and white blood cell.
- **Evaluation:** This statement is incorrect as well. Lymph is a fluid that is similar to plasma but contains fewer proteins and primarily consists of white blood cells (especially lymphocytes). It does not contain red blood cells.

4. **Analyze the Fourth Option:**
- **Statement:** Blood is equal to plasma plus red blood cell, then white blood cell, then platelets.
- **Evaluation:** This statement is correct. Blood is composed of plasma (the liquid component) and cellular components, which include red blood cells (RBCs), white blood cells (WBCs), and platelets. Plasma makes up about 55% of blood, while the cellular components make up the remaining 45%.

### Conclusion:
The correct answer is the fourth option: **Blood is equal to plasma plus red blood cell, then white blood cell, then platelets.**

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