A doctor advised a person to take an injection of insulin because

Options

A. his blood pressure was low
B. his heart was beating slowly
C. he was suffering from goitre
D. his sugar level in blood was high

Explanation

**Step-by-Step Solution:**

1. **Understanding Insulin**: Insulin is a hormone produced by the pancreas. Its primary function is to regulate blood sugar levels by facilitating the uptake of glucose into the cells.

2. **Role of Insulin in Blood Sugar Regulation**: When we consume food, especially carbohydrates, our blood sugar levels rise. Insulin helps lower these levels by promoting the absorption of glucose into cells, where it can be used for energy or stored for future use.

3. **Consequences of Insulin Deficiency**: If the pancreas does not produce enough insulin, or if the body becomes resistant to insulin, blood sugar levels can rise significantly. This condition is known as hyperglycemia.

4. **Diabetes Mellitus**: Chronic high blood sugar levels can lead to diabetes mellitus, a serious health condition that can cause various complications if not managed properly.

5. **Medical Intervention**: To manage high blood sugar levels in individuals diagnosed with diabetes, doctors may prescribe insulin injections. This external supply of insulin helps to regulate blood sugar levels effectively.

6. **Conclusion**: Therefore, if a doctor advises a person to take an injection of insulin, it is primarily because their blood sugar level is high, indicating a deficiency or ineffectiveness of insulin in their body.

**Final Answer**: The doctor advised the person to take an injection of insulin because his sugar level in the blood was high.

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