[Solved] If your goal in this course is to achieve a particular grade, what kind of goal have you set? A)A challenging goal B)A learning goal C)A performance goal D)An outcome goal E)A proximal goal 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.