Diffusion across the cell membrane. Look how the red balls went into the cell by diffusion. This is how organisms get things into and out of the cell. Contractile vacuole for osmoregulation. The control of osmosis, the diffusion of water, into the cell.
Earthworms have a closed circulatory system with aortic arches for pumping blood.
Like a primative heart. They are the most like the Human circulatory system. Grasshoppers have and open circulatory system with only a dorsal blood vessel. Not very efficient. Xylem are dead left over cell walls that cannot carry on life functions.