Sweating has a cooling effect because of water's high __________.

• A. buffering capacity
• B. surface tension
• C. specific heat
• D. heat of vaporization

Answer: (D)

Verified step by step guidance

1. Understand the concept of 'heat of vaporization': It is the amount of energy required to convert a given amount of a liquid into a gas at constant temperature and pressure. This property is significant in biological systems for temperature regulation.
2. Recognize that sweating involves the evaporation of water from the skin surface. This process requires energy, which is absorbed from the body, leading to a cooling effect.
3. Identify that the 'heat of vaporization' is the correct term that explains why sweating cools the body. It refers to the energy needed to change water from liquid to vapor, which is a key factor in the cooling process.
4. Differentiate between the given options: 'buffering capacity' relates to pH stability, 'surface tension' refers to the cohesive forces at the surface of a liquid, and 'specific heat' is the energy required to change the temperature of a substance. None of these directly explain the cooling effect of sweating.
5. Conclude that the high 'heat of vaporization' of water is the reason sweating effectively cools the body, as it allows for significant heat absorption during the evaporation process.