Final answer:
Synovial fluid has a high viscosity, which helps in lubricating and cushioning the joints by providing a thick and slow-flowing substance that reduces friction between cartilages.
Step-by-step explanation:
The characteristic of synovial fluid is that it has a high viscosity. Synovial fluid is the lubricating fluid within a synovial joint, which helps to reduce friction between the articular cartilage of synovial joints during movement. This fluid has a higher viscosity than water, meaning it flows more slowly and has a greater resistance to flow. Viscosity is a measure of a fluid's resistance to flow and is influenced by the intermolecular interactions within the fluid. Since synovial fluid helps in cushioning joints and facilitating smooth movement, it is essential that it has a thick, viscous nature.