[Solved] Hillary is recalling details from her most recent trip to Disney World. Which lobe of her brain is most active? A) right frontal B) left frontal C) right temporal D) left temporal Endoderm: The innermost of the three primary germ layers in the embryo, giving rise to the lining of the digestive and respiratory systems. 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.