Which of the following pair of substance play very important role in clotting of blood?

Options

A. Potassium oxalate and sodium citrate
B. Calcium ions and platelet factors
C. Platelet factors and oxalates
D. Heparin and citrates

Answer

To determine which pair of substances plays a very important role in the clotting of blood, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Blood Clotting**: Blood clotting, or coagulation, is a complex process that prevents excessive bleeding when a blood vessel is injured. It involves various components, including platelets and clotting factors.

2. **Identify Key Players in Clotting**: The two main components that are crucial for blood clotting are:
- **Platelets**: These are small cell fragments that play a significant role in the clotting process.
- **Calcium Ions (Ca²⁺)**: Calcium ions are essential for several steps in the coagulation cascade, including the conversion of prothrombin to thrombin.

3. **Evaluate Given Options**: The question provides several pairs of substances. We need to identify which pair includes both platelets and calcium ions, as these are critical for the clotting process.
- **Potassium oxalate and sodium citrate**: These substances are anticoagulants and do not play a role in clotting.
- **Calcium ions and platelet factors**: This pair is correct as both are essential for blood clotting.
- **Platelet factor and oxalate**: This is incorrect as oxalate is an anticoagulant.
- **Heparin and citrate**: Both are anticoagulants and do not promote clotting.

4. **Conclusion**: The correct answer is the pair of **calcium ions and platelet factors**, as both are crucial for the clotting process.

### Final Answer:
The pair of substances that play a very important role in the clotting of blood is **calcium ions and platelet factors**.

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