Question

1. use several examples each to explain how water is essential to the human body with respect to the following properties: a. water acts as a solvent b. water acts as a temperature moderator c. water acts as a lubricant and transportation facilitator

Explanation:

• a. Water acts as a Solvent: Water is a universal solvent due to its polar nature. It dissolves many substances like salts (e.g., NaCl) and sugars (e.g., glucose). In the human body, it helps in transporting nutrients (e.g., dissolved amino - acids) and waste products (e.g., urea dissolved in blood plasma).
• b. Water acts as a Temperature Moderator: Water has a high specific heat capacity. The human body is mostly water. When the body is exposed to heat, water in the body absorbs a large amount of heat without a significant increase in temperature. For example, during physical activity, sweat (which is mostly water) evaporates. The heat required for evaporation is taken from the body, thus cooling it down.
• c. Water acts as a Lubricant and Transportation Facilitator: In joints, synovial fluid (which has a high water content) acts as a lubricant, reducing friction between bones. As a transportation facilitator, in the digestive system, water helps in the movement of food through the digestive tract. For instance, chyme (partially digested food) moves through the intestines with the help of water - based digestive juices.

Answer:

• a. Water acts as a Solvent: Dissolves nutrients (e.g., amino - acids) and waste (e.g., urea) for transport.
• b. Water acts as a Temperature Moderator: High specific heat capacity helps regulate body temperature (e.g., sweat evaporation cools the body).
• c. Water acts as a Lubricant and Transportation Facilitator: Synovial fluid (water - rich) lubricates joints; helps move food (e.g., chyme) in the digestive tract.