Which of the following cannot clot?

Options

A. Lymph only
B. Plasma only
C. Serum only
D. Lymph and serum

Answer

To determine which of the following cannot clot, we need to understand the components involved in the clotting process. Here’s a step-by-step solution:

### Step 1: Understand Blood Components
Blood consists of various components, including red blood cells, white blood cells, platelets, and plasma. Plasma is the liquid part of blood that contains water, electrolytes, proteins, hormones, and waste products.

### Step 2: Identify Clotting Factors
Clotting factors are specific proteins in the blood that are essential for the clotting process. The primary clotting factors include prothrombin and fibrinogen. These proteins play crucial roles in the coagulation cascade, which leads to the formation of a blood clot.

### Step 3: Differentiate Between Plasma and Serum
Plasma is the fluid component of blood that contains clotting factors. When blood clots, the clotting factors are used up, and the remaining liquid is called serum. Serum does not contain clotting factors, meaning it cannot initiate or support the clotting process.

### Step 4: Conclusion
Since serum lacks clotting proteins, it cannot clot. Therefore, the answer to the question "Which of the following cannot clot?" is serum.

### Final Answer
The component that cannot clot is **serum**.

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