👉 A fluid is a substance that takes the shape of its container while maintaining a constant volume. The primary fluids in the human body are water and blood. Water, which makes up about 60% of an adult's body weight, is essential for numerous biological processes, including temperature regulation, nutrient transport, and waste elimination. Blood, composed mainly of water (about 90%), acts as the body's transportation system, carrying oxygen, nutrients, hormones, and waste products to and from cells. Both fluids are crucial for maintaining homeostasis and overall bodily function.
