All animals require a number of chemicals for the formation of body structures and for life processes. These nutrient chemicals are similar throughout the animal kingdom because of the basic chemical similarity of all animal life. Most invertebrates acquire the necessary nutrients from their food, but microorganisms sometimes provide nutrients that are lacking in the food and, especially in marine environments, direct uptake of nutrients from the water may be important.
Keywords: chemoautotrophic bacteria; microorganism; nutrient balance; photosynthesis; symbiosis; wood-feeding; viviparous insect; yolk








