A clam uses its singular foot to dig down into the sand and draw nourishment into its palps, which are filled with mucus. The clam uses a filter-like siphon to transport food into its mouth, where a second filter-like siphon removes water.
According to HowStuffWorks, there are gills made up of double pairs of sheetlike folds containing microscopic pores that are located on each side of the foot, within the clam's mantle cavity. The clam's cilia-covered gills extract oxygen and particles of food from the water. The clam's single foot agitates sand particles and scoops microscopic organic compounds into the clam's body for sustenance.