Final answer:
Cells lining blood vessels perform diffusion, osmosis, and filtration to circulate substances throughout the body.
Step-by-step explanation:
The cells that are in direct contact with each other lining blood vessels and body cavities serve multiple functions, including diffusion, osmosis, and filtration. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. Osmosis specifically refers to the diffusion of water across a semi-permeable membrane, while filtration is the movement of water and solutes across the membrane due to hydrostatic pressure. Each of these processes plays a critical role in the cardiovascular system to circulate gases, nutrients, and wastes to and from the cells of the body.