[Solved] The objective of facilitation and control in the budget process is to ensure actual operations conform as closely as possible to the approved budget. Digestive Tube: A continuous hollow tube extending from the mouth to the anus, through which food is processed and nutrients absorbed. Plankton: Free-floating, mainly microscopic aquatic organisms found in the upper layers of the water; consisting of phytoplankton and zooplankton. Compare with nekton. Microscopic Organisms: Organisms too small to be seen with the naked eye, often including bacteria, archaea, some fungi, and protists. Anus: The distal end and outlet of the digestive tract.