## **Core Concept**
The resistance of tissues to electric current entry depends on their composition, particularly their water content and electrolyte concentration. Tissues with low water content and low electrolyte concentration tend to be more resistant to electric current.

## **Why the Correct Answer is Right**
The correct answer, **D. Bone**, is right because bone tissue has a low water content and a high concentration of minerals such as hydroxyapatite, which makes it a poor conductor of electricity. This results in high electrical resistance. Bone acts as an insulator compared to other tissues like muscle, blood, and skin (which has a high water content and electrolyte concentration), making it more resistant to electric current entry.

## **Why Each Wrong Option is Incorrect**
- **Option A: Blood** is incorrect because blood has a high water content and a significant concentration of electrolytes (like sodium, potassium, and chloride ions), making it a good conductor of electricity with low resistance.
- **Option B: Muscle** is incorrect because muscle tissue also has a high water content and electrolyte concentration, similar to blood, which allows it to conduct electricity with relatively low resistance.
- **Option C: Skin** is incorrect because, although skin can provide some resistance due to its outer layer (stratum corneum), it is still less resistant compared to bone due to its moisture and electrolyte content.

## **Clinical Pearl / High-Yield Fact**
A memorable point for exams is that the resistance of tissues to electrical current is crucial in understanding electrical injuries. **Bone is more resistant to electrical current than soft tissues**, which is why electrical injuries often cause more damage to soft tissues (like muscles and nerves) that are in the path of the current.

## **Correct Answer: D. Bone**