[Solved] The total mean is the mean of a variable over all observations. 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. Mouth: The opening in the face of a person or animal, used for eating, breathing, and speaking. Sea Star: Marine invertebrates belonging to the class Asteroidea, known for their star-shaped body and ability to regenerate limbs.