Mollusks contain a large amount of invertebrate in this phylum. There are about 85, 000 species of recognized mollusks, and over time these numbers will grow. Mollusks are the largest of the marine phyla. There is about 9-10 taxonomic classes in this phylum. Mollusks have the most varying and diverse body structures that there is no one way to describe this phylum as a whole, from snail with shells to colossal squids the size and shape vastly differ. A striking feature for these creatures is that they contain one organ that can perform various tasks for the organism. Most organisms have a mantle with a significant place for breathing and excretion, and a structural nervous system. Many mollusks, when it comes to reproduction, produce eggs containing larvae. Though some mollusks may seem colorful and nice, looks can be extremely deceiving; for these creatures represent serious hazards for human activities.