Percentage of water in adult human body is :

Question

Accepted Answer

The percentage of water in the adult human body is a crucial aspect of human physiology. According to the given correct answer, Option 3, which states that 70% of the adult human body is composed of water, is the correct choice. Here is a detailed explanation supporting this:

1. **Explanation for Option 3 (70%)**:
   - Water is a fundamental component of the human body, playing a vital role in various physiological processes, including temperature regulation, nutrient transport, and waste elimination.
   - On average, the human body is composed of approximately 60-70% water. This percentage can vary based on factors such as age, sex, and body composition. However, 70% is a commonly cited figure in many scientific sources, especially when considering the body composition of a healthy adult.
   - The 70% figure accounts for the water content in various tissues and organs, such as muscles, which are about 75% water, and the brain, which is approximately 73% water. These high percentages contribute to the overall average of 70% for the entire body.

2. **Explanation for why other options are incorrect**:
   - **Option 1 (50%)**: While water constitutes a significant portion of the human body, 50% is generally considered too low for an average adult. This figure might be more applicable to individuals with higher body fat percentages, as fat tissue contains less water compared to muscle.
   - **Option 2 (60%)**: Although 60% is a commonly cited figure for the average water content in the human body, the question specifies that the correct answer is 70%. Therefore, while 60% is close, it does not align with the given correct answer.
   - **Option 4 (80%)**: An 80% water composition is typically too high for an adult human body. Such a high percentage might be more applicable to certain organisms or specific conditions but not to the average adult human.

In conclusion, Option 3, which states that 70% of the adult human body is composed of water, is supported by scientific understanding of human physiology and aligns with the given correct answer.